Mechanism of Enzyme action

TOPIC # 3

In previous blog we have studied two hypothesis of enzyme action now in this blog we will study reaction mechanism of enzyme ,its molecular geometry and energy changes during reaction.

1-REACTION MECHANISM:

In any chemical rection substrate (reactant) converted into product.

Substrate = product ( there may be more substrates or products but it does not matter with concentration).

In enzymatic catalyzed reaction substrate first make covalent bond with aminoacids of active site of enzyme and form complex called as Enzyme substrate complex then substrate changed into product by enzyme and form enzyme product complex and then products leave the enzyme.

REACTION:

Substrate + enzyme = Enzyme substrate complex = Enzyme product complex = Substrate + product.

At the end of reaction Enzyme restored completly while substrate finally changed into product and enzyme is free for 2nd substrate attack.

Keep one point in mind reaction direction is always from substrate into product.

2-MOLECULAR GEOMETRY:

Enzyme is globular protein.Enzyme has two site active site and allosteric site.

Substrate attach to active site of an enzyme.

Substrate attach to enzyme either by lock and key hypothesis or induced fit hypothesis.

Substrate fit exactly in active site of an enzyme and form covalent bond with aminoacids of an enzyme,Enzyme strech the substrate molecule and broke the internal bond of substrate molecule and form new bonds which results in new structure of substrate molecule called as product.

Enzyme also provide proper condition for substrate molecule than outside enviornment therefore substrate likely converted into product through enzyme.

When product is formed it leaves the enzyme and enzyme prepare itself for new reaction.

3-ENERGY CHANGES:

For every chemical reaction to occurs the activation energy is needed.

WHAT IS ACTIVATION ENERGY:

The minimum amount of energy requires to start a reaction.

The energy needed for every chemical reaction to occurs.

This energy is present in cell in form of mechanical energy ATP.

In absence of catalyst reaction occurs very slowly they require a ot of time to complete because reactant molecules collide to form huge amount of energy (activation energy) ro occur.

Allah almighty has created a lot of molecules to act as catalyst to speed up of biochemical or chemical reaction.

The main function of catalyst is to reduce activation energy and speed up of a reaction.

Enzyme act as catalyst in biochemical reaction to reduce or lower the activation energy these molecules are made up of proteins which are organic compound.

FOR EXAMPLE:

The reaxtion ( 2(H2O2) = water + oxygen ) requires a huge amount of energy 86 kj and it takes more time to complete.

This reaction when occurs in presence of enzyme catalase it requires only 1 kj energy and it takes less time as compared to previous reaction.

IMPORTANT MCQS IN THIS TOPIC:

1-Enzymes and substrate make _bond:

Answer: COVALENT BOND

2-The minimum amount of energy requires to complete a reaction to occurs:

Answer: ACTIVATION ENERGY

3-The activation energy is _type of energy:

Answer: MECHANICAL ENERGY (ATP)

4-The main function of enzyme is :

Answer: REDUCES ACTIVATION ENERGY