Enzyme is a biological catalyst which speed up the bio chemical reactions without themselves being used up.
v A non-protenous part of enzyme essential for its proper functioning is called co-factor.
TYPES OF COFACTORS
2) Prosthetic group
v The detachable co-factor is known as an Activator if it is an inorganic ion e.g. Mg+2 ,Fe+2 ,Zn+2 ,Cu+2 etc.
v If the non-protein part is covalently bonded then it is called prosthetic group.
v If the non protein part is loosely attached to the protein part then it is called coenzyme.
v An enzyme with its co-enzyme or prosthetic group removed is called apoenzyme.
v An activated enzyme consisting of polypeptide chain and a factor is known as holoenzyme
v The active site of an enzyme is a three dimensional cavity bearing a specific charge by which the enzyme reacts with its substrate.
COMPOSITION OF ACTIVE SITE
v The active site of the enzyme is made up of two definite region
1) catalytic site
2) binding site
The substance on which enzyme acts is called substrate.
LOCK AND KEY MODEL
v According to lock and key model as a specific key can open a specific lock in the same manner a specific enzyme convert a specific substrate into product.
v According to lock and key model, the active site is a rigid structure.
INDUCE FIT MODEL
v Induce fit model proposes that when a substrate combine with an emzyme, it induces changes in the emzyme structure.
v The temperature at which the rate of reaction is maximum is called optimum temperature. For enzymes of Human body 37oC is the optimum temperature.
v The pH at which the rate of reaction is maximum is called optimum pH.
v The chemical substances which inhibits the rate of reaction are called inhibitors.
TYPES OF INHIBITORS
1) Irreversible inhibitors: Irreversible inhibitors occupy the active site by forming covalent bonds
2) Reversible inhibitors:
TYPES OF REVERSIBLE INHIBITORS
1) Competitive inhibitors
2) Noncompetitive inhibitors