Formation of amino acid in plant .
Updated: Aug 2, 2020
Amino acid :-
There are 20 types of amino acids. In which some amino acids are formed in the cytoplasm of the cell, some in the matrix of mitochondria and some are formed in the stroma (inner space of chloroplast). Amino acids are derived from the intermediates of Glycolysis, TCA cycle, HMP shunt. From Glycolysis we get amino acids like Tryptophan, Phenylalanine, Tyrosine etc. From Calvin cycle we get amino acids like Histidine, Serine, Glycine, Cysteine, Alanine, Valine, Leucine, Isoleucine etc. From TCA cycle we get amino acids like Asparagine, Methionine,Threonine, Lysine, Glutamine, Proline, Arginine etc.
In plants, nitrogen is first assimilated into organic compounds in the form of glutamate, formed from alpha-ketoglutarate and ammonia in the mitochondrion. For other amino acids, plants use transaminases to move the amino group from glutamate to another alpha-keto acids. For example, aspartate aminotransferase converts glutamate and oxaloacetate to alpha-ketoglutarate and aspartate.Other organisms use transaminases for amino acid synthesis, too.
Nonstandard amino acids are usually formed through modifications to standard amino acids.For example, homocysteine is formed through the transsulfuration pathway or by the demethylation of methionine via the intermediate metabolite S-adenosyl methionine, while hydroxyproline is made by a post translational modification of proline. Microorganisms and plants synthesize many uncommon amino acids.For example, some microbes make 2-aminoisobutyric acid and lanthionine, which is a sulfide-bridged derivative of alanine.Both of these amino acids are found in peptidic lantibiotics such as aslamethicin.
However, in plants, 1-aminocyclopropane-1-carboxylic acid is a small disubstituted cyclic amino acid that is a key intermediate in the production of the plant hormone ethylene.
M Sc. in Genetics.