PG1005. Lecture 10. Enzyme Function & Regulation

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "PG1005. Lecture 10. Enzyme Function & Regulation"

Transcription

1 PG1005 Lecture 10 Enzyme Function & Regulation Dr. Neil Docherty

2 My Teaching Objectives 1) Introduce the concept of enzymes as catalysts in terms of their effects on the activation energy and dynamics of biochemical creactions 2) Classify enzyme types and mechanisms of enzymatic catalysis 3) Illustrate how enzyme activity can be quantitatively measured through plots of substrate concentration versus product formation (enzyme kinetics) 4) Highlight mechanisms relevant in the pharmacological and physiological regulation of enzyme activity

3 Chemical Reactions and Activation Energy Consider the following chemical reaction with entering group A and leaving group C A + BC A---B----C AB+C This transition requires free energy input ( G positive) WHY? Chemical reactions require reactants to come within bond forming distance to react Energy input increases the frequency of collision promoting reaction Consider; heat and reactant concentrations and rates

4 Enzymes as Catalysts Enzymes bind substrates and lower the activation energy required for the acquisition of a transition state and subsequent generation of product Key Points 1) The active site environment stabilises/ promotes formation of the transition state intermediate 2) The enzyme remains unchanged at the end of catalysis 3) Enzymes do not alter the equilibrium of forward and reverse reactions Question: Why might equilibrium be of limited physiological relevance?

5 Substrates are Accommodated by the Induced Fit Mechanism Enzyme-substrate hydrogen bonding assists In free energy release and underpins the reduction in activation energy observed in the presence of enzyme

6 Mechanisms of Catalysis at Active Site Combinations of the following catalytic mechanisms occur enzyme active sites: 1. Proximity Based Catalysis 2. Acid-Base Catalysis 3. Strain Based Catalysis ( bond breaking reactions) 4. Covalent Catalysis ( group transfers)

7 Prosthetic Groups. Co-factors and Co-Enzymes Biological catalysts are usually proteins (enzymes) but often Incorporate non-protein molecules that participate in catalysis 1.Prosthetic Groups Most commonly metals (Zn,Cu Mg). Bind tightly to protein core and participate in REDOX reactions or alter substrate reactivity. 2. Co-factors Also frequently metals, available in medium to bind transiently to enzyme or substrate 3. Coenzymes Frequently B vitamin derivates operative in shuttling of protons and functional groups.

8 Examples of Enzyme Cofactors

9 Enzyme Types The suffix ase denotes an enzyme ACTIVITY (e.g dehydrogenase, protease, lipase etc..) SUBSTRATE /SOURCE lactate serine pancreatic NOT SYSTEMATIC International Union of Biochemists Nomenclature

10 Enzyme Nomenclature Six groups: 1) Oxidoreductases 2) Transferases 3) Hydrolases 4) Lyases 5) Isomerases 6) Ligases e.g. HEXOKINASE Transfers a phosphoryl group to six carbon sugars (see glycolysis) 2. Transferase 7. Subclass (phosphoryl transfer 1. Subclass (alcohol is acceptor) 2. First enzyme of this class or, ATP:D-hexose 6 phosphotransferase

11 Rates of Enzymatic Reaction Temperature optimum in humans is circa 37 C ph optimum generally between 5 and 9 (N.B. pepsin is auto-activated from a precursor in the stomach in HCl conditioned low ph) N.B. Think of effect of temperature and ph on protein folding and ionisation of amino acid side chains AND HENCE ACTIVE SITE STRUCTURAL CHEMISTRY (For Monomeric Enzymes) Reaction rate increases upon increasing substrate until saturating concentrations of substrate Increasing enzyme concentration in presence of excess substrate elevates the point at which the maximum rate of reaction is reached

12 Useful Kinetic Data (Monomeric Enzymes) Michaelis and Menton (1913) Vmax-Rate of reaction (product formation/unit time) when enzyme is saturated High Vmax=rapid catalysis Km- Substrate concentration yielding 1/2 Vmax. Describes the affinity of an enzyme for substrate. Low Km=high affinity

13 Lineweaver-Burk Plots Plot reciprocals

14 Reversible Enzyme Inhibition 1) Competitive e.g) ibuprofen 2) Uncompetitive e.g. herbicides 3) Non-competitive e.g. deoxycyline

15 Irreversible Inhibition -Group-specific (react with specific active site amino acid side chains) -Reactive substrate analogues (covalent binding at active site) -Suicide inhibitors (substrate or transition state analogues generating a reactive intermediate that inactivates enzyme via covalent modification)

16 Physiological Regulation of Enzyme Activity 1.Allosteric Control -Product feedback effect on rate limiting step in pathway 2. Isoenzymes Same reaction, more than one enzyme with differing characteristics e.g. Km 3. Reversible Covalent modification Phosphorylation 4. Proteolytic activation Gastrointestinal zymogens 5. Enzyme synthesis and degradation Transcription, tagging and proteosomal degradation

17 Your Learning From Today Should focus on being able to; 1) Describe how enzymes affect the rate of biochemical reactions and why this is useful in the body 2) Classify enzyme types and mechanisms of enzymatic catalysis 3) Outline how enzyme activity can be quantitatively measured through plots of substrate concentration versus product formation (enzyme kinetics) 4) Explain the mechanisms relevant in the pharmacological and physiological regulation of enzyme activity

Chapter 19 Enzymes and Vitamins

Chapter 19 Enzymes and Vitamins 1.! What are enzymes? Be able to describe the chemical nature of enzymes and their function in biochemical reactions.! 2.! How do enzymes work, and why are they so specific? Be able to provide an overview

More information

Energy & Enzymes. Life requires energy for maintenance of order, growth, and reproduction. The energy living things use is chemical energy.

Energy & Enzymes. Life requires energy for maintenance of order, growth, and reproduction. The energy living things use is chemical energy. Energy & Enzymes Life requires energy for maintenance of order, growth, and reproduction. The energy living things use is chemical energy. 1 Energy exists in two forms - potential and kinetic. Potential

More information

Enzymes. Enzyme Structure. Enzyme Classification. CHEM464/Medh, J.D. Reaction Rate and Enzyme Activity

Enzymes. Enzyme Structure. Enzyme Classification. CHEM464/Medh, J.D. Reaction Rate and Enzyme Activity Enzymes Enzymes are biological catalysts They are not consumed or altered during the reaction They do not change the equilibrium, just reduce the time required to reach equilibrium. They increase the rate

More information

ENZYMES 2H 2 O 2 O 2 + 2H 2 O WHAT ARE ENZYMES? WHAT DO ENZYMES DO?

ENZYMES 2H 2 O 2 O 2 + 2H 2 O WHAT ARE ENZYMES? WHAT DO ENZYMES DO? ENZYMES WHAT ARE ENZYMES? WHAT DO ENZYMES DO? catalase 2H 2 O 2 O 2 + 2H 2 O catalase There are literally thousands of different enzymes which catalyze every major chemical reaction in the cells and bodies

More information

2-An activated enzyme made of polypeptide chain and a co-factor is (A) Coenzyme (B) Substrate (C) Apoenzyme (D) Holoenzyme

2-An activated enzyme made of polypeptide chain and a co-factor is (A) Coenzyme (B) Substrate (C) Apoenzyme (D) Holoenzyme 1-The catalytic activity of an enzyme is restricted to its small portion called (B) Passive site (C) Allosteric site (D) All Choices are correct 2-An activated enzyme made of polypeptide chain and a co-factor

More information

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. Ch19_PT MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Enzymes are members of which class of biomolecules? A) carbohydrates B) nucleic acids C)

More information

Chapter 8: Energy and Metabolism

Chapter 8: Energy and Metabolism Chapter 8: Energy and Metabolism 1. Discuss energy conversions and the 1 st and 2 nd law of thermodynamics. Be sure to use the terms work, potential energy, kinetic energy, and entropy. 2. What are Joules

More information

Learning Objectives. Learning Objectives (cont.) Chapter 6: Metabolism - Energy & Enzymes 1. Lectures by Tariq Alalwan, Ph.D.

Learning Objectives. Learning Objectives (cont.) Chapter 6: Metabolism - Energy & Enzymes 1. Lectures by Tariq Alalwan, Ph.D. Biology, 10e Sylvia S. Mader Lectures by Tariq Alalwan, Ph.D. Learning Objectives Define energy, emphasizing how it is related to work and to heat State and apply two energy laws to energy transformations.

More information

Enzymes reduce the activation energy

Enzymes reduce the activation energy Enzymes reduce the activation energy Transition state is an unstable transitory combination of reactant molecules which occurs at the potential energy maximum (free energy maximum). Note - the ΔG of the

More information

Spontaneous Reactions

Spontaneous Reactions Enzymes Spontaneous Reactions May occur quickly or slowly Enzymes speed up chemical reactions!! (But how, Ms. Robinson????) An enzyme is a macromolecule that acts as a catalyst a chemical agent that speeds

More information

Enzymes. Enzymes are characterized by: Specificity - highly specific for substrates

Enzymes. Enzymes are characterized by: Specificity - highly specific for substrates Enzymes Enzymes are characterized by: Catalytic Power - rates are 10 6-10 12 greater than corresponding uncatalyzed reactions Specificity - highly specific for substrates Regulation - acheived in many

More information

1. A covalent bond between two atoms represents what kind of energy? a. Kinetic energy b. Potential energy c. Mechanical energy d.

1. A covalent bond between two atoms represents what kind of energy? a. Kinetic energy b. Potential energy c. Mechanical energy d. 1. A covalent bond between two atoms represents what kind of energy? a. Kinetic energy b. Potential energy c. Mechanical energy d. Solar energy A. Answer a is incorrect. Kinetic energy is the energy of

More information

4. Which of the following is always present in both conjugated enzymes and simple enzymes? A) protein B) a vitamin C) a cofactor D) a coenzyme

4. Which of the following is always present in both conjugated enzymes and simple enzymes? A) protein B) a vitamin C) a cofactor D) a coenzyme Chem 121 Sample Question Chapter 21: Enzymes and Vitamins 1. What is the function of enzymes within living systems? A) structural elements B) neurotransmitters C) catalysts D) hormones 2. Enzymes have

More information

Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Two Forms of Energy

Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Two Forms of Energy Module 2D - Energy and Metabolism Objective # 19 All living organisms require energy for survival. In this module we will examine some general principles about chemical reactions and energy usage within

More information

What do Enzyme ACTUALLY do?

What do Enzyme ACTUALLY do? Enzyme Kinetics Virtually All Reactions in Cells Are Mediated by Enzymes Enzymes catalyze thermodynamically favorable reactions, causing them to proceed at extraordinarily rapid rates Enzymes provide cells

More information

BIOCHEMISTRY (I) LIFS2210. Enzymes and Enzyme Reactions

BIOCHEMISTRY (I) LIFS2210. Enzymes and Enzyme Reactions BIOCHEMISTRY (I) LIFS2210 Enzymes and Enzyme Reactions 1 1. Enzymes: Biocatalysts Catalyst: to increase the rate or velocity of a chemical reaction without itself being changed in the overall process Catalyst

More information

An Introduction to Metabolism. Chapter 8

An Introduction to Metabolism. Chapter 8 An Introduction to Metabolism Chapter 8 METABOLISM I. Introduction All of an organism s chemical reactions Thousands of reactions in a cell Example: digest starch use sugar for energy and to build new

More information

CHAPTER 6 AN INTRODUCTION TO METABOLISM. Section B: Enzymes

CHAPTER 6 AN INTRODUCTION TO METABOLISM. Section B: Enzymes CHAPTER 6 AN INTRODUCTION TO METABOLISM Section B: Enzymes 1. Enzymes speed up metabolic reactions by lowering energy barriers 2. Enzymes are substrate specific 3. The active site in an enzyme s catalytic

More information

Anabolic and Catabolic Reactions are Linked by ATP in Living Organisms

Anabolic and Catabolic Reactions are Linked by ATP in Living Organisms Chapter 5: Microbial Metabolism Microbial Metabolism Metabolism refers to all chemical reactions that occur within a living a living organism. These chemical reactions are generally of two types: Catabolic:

More information

Chemistry 20 Chapters 15 Enzymes

Chemistry 20 Chapters 15 Enzymes Chemistry 20 Chapters 15 Enzymes Enzymes: as a catalyst, an enzyme increases the rate of a reaction by changing the way a reaction takes place, but is itself not changed at the end of the reaction. An

More information

Ch. 8 Enzymes as catalysts

Ch. 8 Enzymes as catalysts Chapt. 8 Enzymes as catalysts Ch. 8 Enzymes as catalysts Student Learning Outcomes: Explain general features of enzymes as catalysts: Substrate -> Product Describe nature of catalytic sites general mechanisms

More information

What affects an enzyme s activity? General environmental factors, such as temperature and ph. Chemicals that specifically influence the enzyme.

What affects an enzyme s activity? General environmental factors, such as temperature and ph. Chemicals that specifically influence the enzyme. CH s 8-9 Respiration & Metabolism Metabolism A catalyst is a chemical agent that speeds up a reaction without being consumed by the reaction. An enzyme is a catalytic protein. Hydrolysis of sucrose by

More information

Enzymes biologic catalysts. macromolecule synthesis

Enzymes biologic catalysts. macromolecule synthesis Enzymes How importance Living procedures based on reaction Catalyst essential to accelerate reactions Enzymes biologic catalysts Without them NO LIFE (KNOWN) movement circulation macromolecule synthesis

More information

Regulation of enzyme activity

Regulation of enzyme activity 1 Regulation of enzyme activity Regulation of enzyme activity is important to coordinate the different metabolic processes. It is also important for homeostasis i.e. to maintain the internal environment

More information

Catalysis by Enzymes. Enzyme A protein that acts as a catalyst for a biochemical reaction.

Catalysis by Enzymes. Enzyme A protein that acts as a catalyst for a biochemical reaction. Catalysis by Enzymes Enzyme A protein that acts as a catalyst for a biochemical reaction. Enzymatic Reaction Specificity Enzyme Cofactors Many enzymes are conjugated proteins that require nonprotein portions

More information

BIOCHEMISTRY/MOLECULAR BIOLOGY

BIOCHEMISTRY/MOLECULAR BIOLOGY Enzymes Activation Energy Chemical reactions require an initial input of energy activation energy large biomolecules are stable must absorb energy to break bonds cellulose energy CO 2 + H 2 O + heat Activation

More information

LAWS OF THERMODYNAMICS First Law: E cannot be created or destroyed, only transformed. Second Law: When E is transformed, some cannot be used for work

LAWS OF THERMODYNAMICS First Law: E cannot be created or destroyed, only transformed. Second Law: When E is transformed, some cannot be used for work ENERGY, ENZYMES AND METABOLISM CHAPTER 8 Lecture Objectives What Physical Principles Underlie Biological Energy Transformations? What Is the Role of ATP in Biochemical Energetics? What Are Enzymes? How

More information

CHAPTER 4: Enzyme Structure ENZYMES

CHAPTER 4: Enzyme Structure ENZYMES CHAPTER 4: ENZYMES Enzymes are biological catalysts. There are about 40,000 different enzymes in human cells, each controlling a different chemical reaction. They increase the rate of reactions by a factor

More information

1. 2. Enzymes. 1: Biochemistry of macromolecules and metabolic pathways

1. 2. Enzymes. 1: Biochemistry of macromolecules and metabolic pathways 1. 2 Enzymes Enzymes are referred to as biological catalysts they create new pathways that allow reactions to occur many times faster than uncatalysed reactions. Enzymes act on specific molecules called

More information

An Introduction to Metabolism

An Introduction to Metabolism Chapter 8 An Introduction to Metabolism Overview: The Energy of Life The living cell is a miniature chemical factory where thousands of reactions occur The cell extracts energy and applies energy to perform

More information

An Introduction to Metabolism

An Introduction to Metabolism Chapter 8 An Introduction to Metabolism PowerPoint Lecture Presentations for Biology Eighth Edition Neil Campbell and Jane Reece Lectures by Chris Romero, updated by Erin Barley with contributions from

More information

Topic 7: METABOLISM: THERMODYNAMICS, CHEMICAL EQUILIBRIA, ENERGY COUPLING and CATALYSIS (lectures 9-10)

Topic 7: METABOLISM: THERMODYNAMICS, CHEMICAL EQUILIBRIA, ENERGY COUPLING and CATALYSIS (lectures 9-10) Topic 7: METABOLISM: THERMODYNAMICS, CHEMICAL EQUILIBRIA, ENERGY COUPLING and CATALYSIS (lectures 9-10) OBJECTIVES: 1. Understand the concepts of kinetic vs. potential energy. 2. Understand the concepts

More information

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. Name Advanced Biology Enzyme and Cellular Respiration Test Part I Multiple Choice (75 points) MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) The

More information

Enzymes and Metabolism

Enzymes and Metabolism Enzymes and Metabolism Enzymes and Metabolism Metabolism: Exergonic and Endergonic Reactions Chemical Reactions: Activation Every chemical reaction involves bond breaking and bond forming A chemical reaction

More information

Lecture 4 Enzymes Catalytic proteins. Enzymes. Enzymes 10/21/10. What enzymes do therefore is:

Lecture 4 Enzymes Catalytic proteins. Enzymes. Enzymes 10/21/10. What enzymes do therefore is: Lecture 4 Catalytic proteins Are a type of protein that acts as a catalyst-speeding up chemical reactions A catalyst is defined as a chemical agent that changes the rate of a reaction without being consumed

More information

Enzymes and Metabolism

Enzymes and Metabolism Enzymes and Metabolism AP Biology Chapter 8 Metabolism Metabolism are all the chemical reactions in an organism Forming bonds between molecules dehydration synthesis synthesis of new muscle tissue by linking

More information

Enzymes and Metabolic Pathways

Enzymes and Metabolic Pathways Enzymes and Metabolic Pathways Enzyme characteristics Made of protein Catalysts: reactions occur 1,000,000 times faster with enzymes Not part of reaction Not changed or affected by reaction Used over and

More information

Lecture 15: Enzymes & Kinetics Mechanisms

Lecture 15: Enzymes & Kinetics Mechanisms ROLE OF THE TRANSITION STATE Lecture 15: Enzymes & Kinetics Mechanisms Consider the reaction: H-O-H + Cl - H-O δ- H Cl δ- HO - + H-Cl Reactants Transition state Products Margaret A. Daugherty Fall 2004

More information

Ch 4: Energy and Cellular Metabolism

Ch 4: Energy and Cellular Metabolism Ch 4: Energy and Cellular Metabolism Energy as it relates to Biology Chemical reactions Enzymes and how they speed rxs Metabolism and metabolic pathways Catabolism (ATP production) Anabolism (Synthesis

More information

Energy Concepts. Study Objectives:

Energy Concepts. Study Objectives: Energy Concepts Study Objectives: 1. Define energy 2.Describe the 1 st law of thermodynamics Compare kinetic and potential energy, be able to give or recognize examples of each 3. Describe the major forms

More information

Free Energy and Enzymes (Chapter 6) Outline. 1. The "extra" electrons have been stripped from other atoms in the cell.

Free Energy and Enzymes (Chapter 6) Outline. 1. The extra electrons have been stripped from other atoms in the cell. Free Energy and Enzymes (Chapter 6) Outline Growing Old With Molecular Mayhem A. Free radicals are molecules with extra electrons. 1. The "extra" electrons have been stripped from other atoms in the cell.

More information

Chapter 8: An Introduction to Metabolism

Chapter 8: An Introduction to Metabolism Chapter 8: An Introduction to Metabolism Name Period Concept 8.1 An organism s metabolism transforms matter and energy, subject to the laws of thermodynamics 1. Define metabolism. The totality of an organism

More information

MULTIPLE CHOICE QUESTIONS

MULTIPLE CHOICE QUESTIONS MULTIPLE CHOICE QUESTIONS 1. Most components of energy conversion systems evolved very early; thus, the most fundamental aspects of energy metabolism tend to be: A. quite different among a diverse group

More information

Intro to Metabolism Campbell Chapter 8

Intro to Metabolism Campbell Chapter 8 Intro to Metabolism Campbell Chapter 8 http://ag.ansc.purdue.edu/sheep/ansc442/semprojs/2003/spiderlamb/eatsheep.gif http://www.gifs.net Section 8.1 An organism s metabolism transforms matter and energy,

More information

The Behavior of Proteins:

The Behavior of Proteins: Mary K. Campbell Shawn O. Farrell http://academic.cengage.com/chemistry/campbell Chapter 7 The Behavior of Proteins: Enzymes, Mechanisms, and Control Paul D. Adams University of Arkansas The catalytic

More information

1. Enzymes. Biochemical Reactions. Chapter 5: Microbial Metabolism. 1. Enzymes. 2. ATP Production. 3. Autotrophic Processes

1. Enzymes. Biochemical Reactions. Chapter 5: Microbial Metabolism. 1. Enzymes. 2. ATP Production. 3. Autotrophic Processes Chapter 5: Microbial Metabolism 1. Enzymes 2. ATP Production 3. Autotrophic Processes 1. Enzymes Biochemical Reactions All living cells depend on biochemical reactions to maintain homeostasis. All of the

More information

The effects that are in play when the enzyme-substrate complex forms: The chains needed for catalysis are in the active site

The effects that are in play when the enzyme-substrate complex forms: The chains needed for catalysis are in the active site The effects that are in play when the enzyme-substrate complex forms: The proximity effect: The orientation effect: The catalytic effect: The energy effect: The enzyme has to join up with the substrate

More information

Lecture 3: Enzyme kinetics

Lecture 3: Enzyme kinetics Computational Systems Biology Lecture 3: Enzyme kinetics Fri 19 Jan 2009 1 Images from: D. L. Nelson, Lehninger Principles of Biochemistry, IV Edition, W. H. Freeman ed. A. Cornish-Bowden Fundamentals

More information

Define the term energy and distinguish between potential and kinetic energy.

Define the term energy and distinguish between potential and kinetic energy. Energy and Chemical Reactions Objective # 1 All living organisms require energy for survival. In this topic we will examine some general principles about energy usage and chemical reactions within cells.

More information

I N V E S T I C E D O R O Z V O J E V Z D Ě L Á V Á N Í ENZYMES

I N V E S T I C E D O R O Z V O J E V Z D Ě L Á V Á N Í ENZYMES = substances that... biological reactions 1. Provide an alternative reaction route which has a lower... energy 2. Reactions catalysed by enzymes occur under mild conditions + good yield + fast 3. Enzymes

More information

What happens to the food we eat? It gets broken down!

What happens to the food we eat? It gets broken down! Enzymes Essential Questions: What is an enzyme? How do enzymes work? What are the properties of enzymes? How do they maintain homeostasis for the body? What happens to the food we eat? It gets broken down!

More information

Regulation of Metabolism. Enzymes and Cellular Energy

Regulation of Metabolism. Enzymes and Cellular Energy Regulation of Metabolism Local (intrinsic) Control Mechanisms Enzymes and Cellular Energy Cellular metabolism consists of: Catabolism: the breakdown of organic molecules Anabolism: the synthesis of organic

More information

Introduction to Enzymes

Introduction to Enzymes Introduction to Enzymes The following has been excerpted from a very popular Worthington publication which was originally published in 1972 as the Manual of Clinical Enzyme Measurements. While some of

More information

Reading Assignment: pp , ,

Reading Assignment: pp , , Chapter 6 "Mechanisms of Enzymes" Reading Assignment: pp. 158-167, 171-176, 182-187. Problem Assignment: 1, 3, and 4. I. Introduction The first objective of this chapter is to obtain a conceptual understanding

More information

It s the amino acids!

It s the amino acids! Catalytic Mechanisms HOW do enzymes do their job? Reducing activation energy sure, but HOW does an enzyme catalysis reduce the energy barrier ΔG? Remember: The rate of a chemical reaction of substrate

More information

Module 1: Enzymes Biology

Module 1: Enzymes Biology State that enzymes are globular proteins, with a specific tertiary structure, which catalyse metabolic reactions in living organisms State that enzyme action may be intracellular or extracellular Specificity,

More information

Ch7 Enzymes II: Coenzymes, Regulation, Abzymes, and Ribozymes 阮雪芬 NTU

Ch7 Enzymes II: Coenzymes, Regulation, Abzymes, and Ribozymes 阮雪芬 NTU Ch7 Enzymes II: Coenzymes, Regulation, Abzymes, and Ribozymes 阮雪芬 2004/04/23 @ NTU Enzyme: Coenzyme Partners Vitamins and coenzymes Coenzyme: an organic or organometallic molecule that assists an enzyme.

More information

Energy and Life. Energy= the ability to do work. Autotrophs= use sunlight, CO 2, and water to make their own food (sugars) PHOTOSYNTHESIS

Energy and Life. Energy= the ability to do work. Autotrophs= use sunlight, CO 2, and water to make their own food (sugars) PHOTOSYNTHESIS Energy and Life Energy= the ability to do work Autotrophs= use sunlight, CO 2, and water to make their own food (sugars) PHOTOSYNTHESIS Heterotrophs= can t make their own food, they have to eat autotrophs

More information

Sindh Text Book Board, Jamshoro.

Sindh Text Book Board, Jamshoro. Chapter 3 ENZYMES Life would not be possible with out metabolic activities of the cell. This in turn is depends upon the Catalytic molecules called the enzymes. With-out enzymes, the dynamic, steady state

More information

General Properties Protein Nature of Enzymes Folded Shape of Enzymes H-bonds complementary

General Properties Protein Nature of Enzymes Folded Shape of Enzymes H-bonds complementary Proteins that function as biological catalysts are called enzymes. Enzymes speed up specific metabolic reactions. Low contamination, low temperature and fast metabolism are only possible with enzymes.

More information

AS Demonstrate understanding of life processes at the cellular level. ENZYMES

AS Demonstrate understanding of life processes at the cellular level. ENZYMES AS 91156 Demonstrate understanding of life processes at the cellular level. ENZYMES (2013: 2) The rate of photosynthesis is directly related to the availability of light. Normally, an increase in light

More information

Enzymes are specialized proteins that catalyze biological reactions, accelerating reaction rates as much as fold over uncatalyzed rates.

Enzymes are specialized proteins that catalyze biological reactions, accelerating reaction rates as much as fold over uncatalyzed rates. Chapters 10 and 11 Enzymes Enzymes are specialized proteins that catalyze biological reactions, accelerating reaction rates as much as 10 6 - fold over uncatalyzed rates. 6 major classes of enzymes: 1)

More information

Chapter 8 An Introduction to Metabolism

Chapter 8 An Introduction to Metabolism Chapter 8 An Introduction to Metabolism Sep 7 9:07 PM 1 Metabolism=all of the chemical reactions within an organism metabolic pathways are chemical reactions that change molecules in a series of steps

More information

Figure 5. Energy of activation with and without an enzyme.

Figure 5. Energy of activation with and without an enzyme. Biology 20 Laboratory ENZYMES & CELLULAR RESPIRATION OBJECTIVE To be able to list the general characteristics of enzymes. To study the effects of enzymes on the rate of chemical reactions. To demonstrate

More information

Chapter 12 - Reaction Kinetics

Chapter 12 - Reaction Kinetics Chapter 12 - Reaction Kinetics In the last chapter we looked at enzyme mechanisms. In this chapter we ll see how enzyme kinetics, i.e., the study of enzyme reaction rates, can be useful in learning more

More information

How Enzymes Lower the E A. Barrier. Substrate Specificity of Enzymes. Enzymes catalyze reac.ons by lowering the E A barrier

How Enzymes Lower the E A. Barrier. Substrate Specificity of Enzymes. Enzymes catalyze reac.ons by lowering the E A barrier How Enzymes Lower the E A Barrier Enzymes catalyze reac.ons by lowering the E A barrier do not affect the change in free energy ( G) Instead hasten reac.ons that would occur eventually Fig. 8 15 Free energy

More information

Proteins. Molecular Physiology: Enzymes and Cell Signaling. Binding. Protein Specificity. Enzymes. Enzymatic Reactions

Proteins. Molecular Physiology: Enzymes and Cell Signaling. Binding. Protein Specificity. Enzymes. Enzymatic Reactions Proteins Molecular Physiology: Enzymes and Cell Signaling Polymers of amino acids Have complex 3D structures Are the basis of most of the structure and physiological function of cells Binding Much of protein

More information

CHAPTER 8: ENERGY AND METABOLISM

CHAPTER 8: ENERGY AND METABOLISM CHAPTER 8: ENERGY AND METABOLISM CHAPTER SYNOPSIS Living organisms transform potential energy into kinetic energy to survive, grow, and reproduce. The energy that the earth receives from the sun is transformed

More information

Unit 2 Metabolism and Survival Summary

Unit 2 Metabolism and Survival Summary Unit 2 Metabolism and Survival Summary 1 Metabolism pathways and their control (a) Introduction to metabolic pathways This involves integrated and controlled pathways of enzymecatalysed reactions within

More information

ENZYME- SUBSTRATE COMPLEX

ENZYME- SUBSTRATE COMPLEX Enzymes OK.so now we ve done all of that hemistry stuff that you all love so much...let s get down to the real stuff aving just learnt about proteins, let s now look at one of the fundamental substances

More information

TECHNICAL UNIVERSITY OF MOMBASA Faculty of ENGINEERING & TECHNOLOGY

TECHNICAL UNIVERSITY OF MOMBASA Faculty of ENGINEERING & TECHNOLOGY TECHNICAL UNIVERSITY OF MOMBASA Faculty of ENGINEERING & TECHNOLOGY DEPARTMENT OF MEDICAL SCIENCES FACULTY OF APPLIED AND HEALTH SCIENCES BMLS 13M MID ENTRY ABT 4202 : BIOCHEMISTRY II INSTRUCTIONS: END

More information

Computational Systems Biology. Lecture 2: Enzymes

Computational Systems Biology. Lecture 2: Enzymes Computational Systems Biology Lecture 2: Enzymes 1 Images from: David L. Nelson, Lehninger Principles of Biochemistry, IV Edition, Freeman ed. or under creative commons license (search for images at http://search.creativecommons.org/)

More information

AP Biology. From food webs to the life of a cell. Metabolism & Enzymes. Flow of energy through life. Metabolism. Chemical reactions of life

AP Biology. From food webs to the life of a cell. Metabolism & Enzymes. Flow of energy through life. Metabolism. Chemical reactions of life From food webs to the life of a cell energy Metabolism & Enzymes energy energy Flow of energy through life Life is built on chemical reactions sun transforming energy from one form to another organic molecules

More information

8/20/2012 H C OH H R. Proteins

8/20/2012 H C OH H R. Proteins Proteins Rubisco monomer = amino acids 20 different amino acids polymer = polypeptide protein can be one or more polypeptide chains folded & bonded together large & complex 3-D shape hemoglobin Amino acids

More information

LAB EXERCISE: Enzymes I Catechol Oxidase

LAB EXERCISE: Enzymes I Catechol Oxidase LAB EXERCISE: Enzymes I Catechol Oxidase Laboratory Objectives After completing this lab topic, you should be able to: 1. Define enzyme and describe the activity of enzymes in cells. 2. Differentiate competitive

More information

ENZYME MECHANISM C H A P T E R 7

ENZYME MECHANISM C H A P T E R 7 C H A P T E R 7 ENZYME MECHANISM Active Site Transition State Catalysis Lock and Key Induced Fit Nonproductive Binding Entropy Strain and Distortion Transition-State Stabilization Transition-State Analogs

More information

What is an Enzyme? Animations

What is an Enzyme? Animations First Catalysts Manganese dioxide (a black powder) will catalyze the breakdown of hydrogen peroxide. Car exhaust pipes use catalytic converters help convert carbon monoxide (CO) and unburned hydrocarbons

More information

ENZYMES UNIVERSITY OF PNG SCHOOL OF MEDICINE AND HEALTH SCIENCES DISCIPLINE OF BIOCHEMISTRY AND MOLECULAR BIOLOGY BMLS II / B

ENZYMES UNIVERSITY OF PNG SCHOOL OF MEDICINE AND HEALTH SCIENCES DISCIPLINE OF BIOCHEMISTRY AND MOLECULAR BIOLOGY BMLS II / B ENZYMES UNIVERSITY OF PNG SCHOOL OF MEDICINE AND HEALTH SCIENCES DISCIPLINE OF BIOCHEMISTRY AND MOLECULAR BIOLOGY BMLS II / B Pharm II / BDS II VJ Temple 1 What are enzymes? Enzymes are organic catalysts

More information

CHM333 LECTURE 13 14: 2/13 15/12 SPRING 2012 Professor Christine Hrycyna

CHM333 LECTURE 13 14: 2/13 15/12 SPRING 2012 Professor Christine Hrycyna INTRODUCTION TO ENZYMES Enzymes are usually proteins (some RNA) In general, names end with suffix ase Enzymes are catalysts increase the rate of a reaction not consumed by the reaction act repeatedly to

More information

must proceed at low temperatures

must proceed at low temperatures Bio 20 Enzymes! In Nature, high temperatures cause chemicals to become highly reactive. BUT, high temperatures in cells cause PROBLEMS Ie.//a high fever causes the body to shut down or an egg in boiling

More information

CHM333 LECTURE 13 14: 2/13 15/13 SPRING 2013 Professor Christine Hrycyna

CHM333 LECTURE 13 14: 2/13 15/13 SPRING 2013 Professor Christine Hrycyna INTRODUCTION TO ENZYMES Enzymes are usually proteins (some RNA) In general, names end with suffix ase Enzymes are catalysts increase the rate of a reaction not consumed by the reaction act repeatedly to

More information

Metabolism and Bioenergetics Part 1: Intro and Acetyl CoA

Metabolism and Bioenergetics Part 1: Intro and Acetyl CoA Take notes while watching the following video tutorials to prepare for the Metabolism Part 2 Activity. Metabolism and Bioenergetics Part 1: Intro and Acetyl CoA Metabolism ALL biochemical reactions involving

More information

Enzymes Enzymes Enzymes: proteins ( metabolic pathways & biological Lysozyme Purification of Enzymes:

Enzymes Enzymes Enzymes: proteins ( metabolic pathways &  biological Lysozyme Purification of Enzymes: Enzymes: Enzymes More than 2000 different enzymes are currently known. The function of enzymes and other catalysts is to lower the activation energy, ΔG, for a reaction and thereby enhance the reaction

More information

Glycolysis. The Glycolytic Pathway. The Reactions of Glycolysis. Fermentation: The Anaerobic Fate of Pyruvate. Control of Metabolic Flux

Glycolysis. The Glycolytic Pathway. The Reactions of Glycolysis. Fermentation: The Anaerobic Fate of Pyruvate. Control of Metabolic Flux Glycolysis The Glycolytic Pathway The Reactions of Glycolysis Fermentation: The Anaerobic Fate of Pyruvate Control of Metabolic Flux Metabolism of Hexoses Other Than Glucose The Glycolytic Pathway (Embden-Meyerhof-Parnas

More information

Enzymes. OpenStax College

Enzymes. OpenStax College OpenStax-CNX module: m44429 1 Enzymes OpenStax College This work is produced by OpenStax-CNX and licensed under the Creative Commons Attribution License 4.0 By the end of this section, you will be able

More information

Cellular physiology ATP and Biological Energy (Lecture 15)

Cellular physiology ATP and Biological Energy (Lecture 15) Cellular physiology ATP and Biological Energy (Lecture 15) The complexity of metabolism This schematic diagram traces only a few hundred of the thousands of metabolic reactions that occur in a cell. The

More information

ACTIVATION ENERGY AND CATALYSIS

ACTIVATION ENERGY AND CATALYSIS Introduction ACTIVATION ENERGY AND CATALYSIS For a reaction to occur, molecules must collide. The frequency of the collisions affects the rate of the reaction. The frequency can be changed by a. increasing

More information

Previous lecture: Today:

Previous lecture: Today: Previous lecture: The energy requiring step from substrate to transition state is an energy barrier called the free energy of activation G Transition state is the unstable (10-13 seconds) highest energy

More information

Protein Function. After the Folding. Lecture 3

Protein Function. After the Folding. Lecture 3 Protein Function After the Folding Lecture 3 Gene to gene product (protein) Protein folding of nascent polypeptide chain - Immediate folding amplification Proteins mediate virtually all cellular functions

More information

ENZYME SCIENCE AND ENGINEERING PROF. SUBHASH CHAND DEPARTMENT OF BIOCHEMICAL ENGINEERING AND BIOTECHNOLOGY IIT DELHI LECTURE 4 ENZYMATIC CATALYSIS

ENZYME SCIENCE AND ENGINEERING PROF. SUBHASH CHAND DEPARTMENT OF BIOCHEMICAL ENGINEERING AND BIOTECHNOLOGY IIT DELHI LECTURE 4 ENZYMATIC CATALYSIS ENZYME SCIENCE AND ENGINEERING PROF. SUBHASH CHAND DEPARTMENT OF BIOCHEMICAL ENGINEERING AND BIOTECHNOLOGY IIT DELHI LECTURE 4 ENZYMATIC CATALYSIS We will continue today our discussion on enzymatic catalysis

More information

2. Give the formula (with names) for the catabolic degradation of glucose by cellular respiration.

2. Give the formula (with names) for the catabolic degradation of glucose by cellular respiration. Chapter 9: Cellular Respiration: Harvesting Chemical Energy Name Period Overview: Before getting involved with the details of cellular respiration and photosynthesis, take a second to look at the big picture.

More information

Briefly explain biosynthesis of cell constituents (requires energy)

Briefly explain biosynthesis of cell constituents (requires energy) 3 Cell Metabolism Chapter 3 Cell Metabolism - review Student Learning Outcomes: Describe central role of enzymes as catalysts Vast array of chemical reactions Many enzymes are proteins Role of NAD + /NADH

More information

Biochemistry -I Prof. S. Dasgupta Department of Chemistry Indian Institute of Chemistry, Kharagpur Lecture # 25 Metabolism - I

Biochemistry -I Prof. S. Dasgupta Department of Chemistry Indian Institute of Chemistry, Kharagpur Lecture # 25 Metabolism - I Biochemistry -I Prof. S. Dasgupta Department of Chemistry Indian Institute of Chemistry, Kharagpur Lecture # 25 Metabolism - I The final chapter of this course deals with metabolism. In metabolism we need

More information

Lecture 8 Enzyme Energetics

Lecture 8 Enzyme Energetics Lecture 8 Enzyme Energetics 1 Last Lecture We talked about protein conformational change, signal cascades, phosphorylation, and ATP. We shall review these things even more in depth today 2 In this lecture

More information

Lecture 11 Enzymes: Kinetics

Lecture 11 Enzymes: Kinetics Lecture 11 Enzymes: Kinetics Reading: Berg, Tymoczko & Stryer, 6th ed., Chapter 8, pp. 216-225 Key Concepts Kinetics is the study of reaction rates (velocities). Study of enzyme kinetics is useful for

More information

Microbial Metabolism. Biochemical diversity

Microbial Metabolism. Biochemical diversity Microbial Metabolism Biochemical diversity Metabolism Define Requirements Energy Enzymes Rate Limiting step Reaction time Types Anabolic Endergonic Dehydration Catabolic Exergonic Hydrolytic Metabolism

More information

Lipids (Biologie Woche 1 und 2; Pages 81 and 82)

Lipids (Biologie Woche 1 und 2; Pages 81 and 82) Lipids (Biologie Woche 1 und 2; Pages 81 and 82) Lipids Features Have oily, greasy or waxy consistency Relatively insoluble in water Protein and carbohydrates may be converted into lipids by enzymes an

More information

An organism s metabolism transforms matter and energy, subject to the laws of thermodynamics [2].

An organism s metabolism transforms matter and energy, subject to the laws of thermodynamics [2]. GUIDED READING - Ch. 8 - AN INTRODUCTION TO METABOLISM NAME: Please print out these pages and HANDWRITE the answers directly on the printouts. Typed work or answers on separate sheets of paper will not

More information

Homework. Due in Lab Week 2. Homework #4 (pages 9, 10 & 11) Biomolecules PreLab #2 (handout up front and on Instructor Website)

Homework. Due in Lab Week 2. Homework #4 (pages 9, 10 & 11) Biomolecules PreLab #2 (handout up front and on Instructor Website) Homework Due in Lab Week 2 Homework #4 (pages 9, 10 & 11) Biomolecules PreLab #2 (handout up front and on Instructor Website) Biological Molecules Enzymes Enzymes One of the most important groups of proteins

More information

Chem 454 Regulatory Mechanisms in Biochemistry Review for Exam I - Spring 2003 Chapter 14 Metabolism: Basic Concepts and Design Classify organisms based on their source of energy. Describe the energy requirements

More information