This document provides information about enzymes and key related concepts. It defines enzymes as substances produced by living organisms that act as catalysts for biochemical reactions in cells. It discusses cofactors, prosthetic groups, and coenzymes that assist enzymes. It also describes apoenzymes and holoenzymes, and characteristics of enzymes like being globular proteins that lower activation energy. The document outlines mechanisms of enzyme action through enzyme-substrate complexes and discusses factors affecting enzymes like temperature and pH. It also introduces the lock-and-key and induced fit models of enzyme-substrate binding and different types of inhibitors.

1. Student Name : Athar Hafeez
Subject: Biochemistry

2. Enzyme
 substance produced by a
living organism which acts as
a catalyst to bring about a
specific biochemical reaction( reactions
that help sustain life and allow cells to grow.)

3. Termsrelatedto
Enzyme
 Cofactor: A cofactor is a non-protein chemical compound or metallic
ion that is required for an enzyme's role as a catalyst. Cofactors can
be considered "helper molecules" that assist in biochemical
transformations
 Prosthetic Group : if the non protein part is covalently bonded to
enzyme then it is called prostatic group
Coenzyme : if non protein part is loosely attached to enzyme
then it is termed as Coenzyme

4. Apoenzyme
&
Holoenzyme
 Apoenzyme or apoprotein is an enzymatically inactive protein part
of an enzyme, which requires a cofactor for its activity
 Holoenzyme is a complete, functional enzyme, which is
catalytically active

5. Characteristics
ofEnzyme
 Enzymes are globular proteins
 The increase the rate of reaction without being used up
 Their presence does not affect the nature or properties
of end products
 Amount of amount of enzyme can accelerate the
chemical reaction
 Enzymes are highly specific
 They are very sensitive to even minor change in pH ,
temperature,and substrate concentration
 They lower activation energy

6. Activational
Energy
 Activation energy is defined as the minimum amount of extra
energy required by a reacting molecule to get converted into
product

7. Mechanismsof
enzymeaction
 An enzyme attracts substrates to its active site, catalyzes the chemical
reaction by which products are formed, and then allows the products
to dissociate (separate from the enzyme surface). The combination
formed by an enzyme and its substrates is called the enzyme–
substrate complex.
 Enzyme + substrate •••• ES complex •••• Enzyme+ product

8. Enzymes
structure
Lock and key model
Lock-and-key model is a model for enzyme-substrate interaction
suggesting that the enzyme and the substrate possess specific
complementary geometric shapes that fit exactly into one another.
Enzymes are highly specific
. Induced Fit model
The induced-fit model states a substrate binds to an active site and
both change shape slightly, creating an ideal fit for catalysis

9. Factorsaffecting
theenzyme
action
 Temperature
 pH value
 Substrate concentration
 Enzyme concentration

10. Inhibitor
An enzyme inhibitor is a molecule that binds
to an enzyme and blocks its activity

11. Typesof
Inhabitor
INHIBITOR
Irreversible
Reversible
Competitive Non-competitive