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A Handbook of Biology

01

02

03

04

The substrate binds to the active site of enzyme (E+S).

This induces some changes in enzyme so that the

substrate is tightly bound with active site of enzyme

to form enzyme-substrate complex (ES)-transition

state.

The active site breaks chemical bonds of substrate to

form enzyme- product complex (EP).

This pathway goes through some unstable transition

state structures.

(NEET 2013)

The enzyme releases the products and the free

enzyme is ready to bind to other molecules of the

substrate (E+P).

E + S

ES

EP

E + P

HØW DØ ËÑZÝMËS SPËËD ÜP Å ÇHËMÏÇÅL RËÅÇTÏØÑ? (ÇØÑÇËPT ØF

ÅÇTÏVÅTÏØÑ ËÑËRGÝ)



Activation

energy

is

the

additional

energy

required

to start a chemical reaction.

(NEET-II 2016)



In

an

exothermic

or

endothermic

reaction,

the

substrate must go through

a much higher energy state.

It is called transition state.

Therefore, activation energy

Transition state

Activation energy

without enzyme

Activation

energy with enzyme

Product (P)

Potential Energy

Progress of reaction

Substrate (s)