Tags: Enzyme.
Aspartokinase or aspartate kinase is an enzyme that catalyzes the phosphorylation of the amino acid aspartate. This reaction is the first step in the biosynthesis of three essential amino acids: methionine lysine and threonine known as the aspartate family. The gene for aspartokinase is present only in microorganisms and plants; it is not present in animals which must obtain aspartate-family amino acids in their diet.