Transamination & Deamination of amino acids

 

1. TRANSMISSION:

The transfer of an amino group (-NH2) from an amino acids to keto acid is known as transmission.  This reaction involves  reversible  transfer  of  a pair  of  amino  acids  and  a pair  of  keto  acids  catalyzed  by a  group  of  enzymes transaminases (Amino transferases). This process is predominantly in liver.

Pyridoxal phosphate is the co-enzyme essential for the transaminase activity. All the amino acids except lysine, proline hydroxy proline and theramine can participate in the transmission reaction.

The keto acids participating in the transamination reaction are only three namely 2 -ketogluturic acid, oxaloacetic acid and pyruvic acid.

2. DECARBOXYLATION:

Decarboxylation is the removal of carboxyl group (-COOH) from an amino acid to form amine with removal of CO2 is called as decarboxylation.  These are catalyzed by the enzyme decarboxylase which requires pyridoxal phosphate as co-enzyme. Decarboxylase enzymes are available in liver, kidney and brain.

3. DIAMINATION:

Deamination means removal of amino group from amino acid in the form of NH3. The ammonia liberated is diverted from urea synthesis. The remaining carbon skeleton of amino acid is catabolised to keto acid. 

Diamination can be:

(2) Oxidative, (2) Non-oxidative

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