Aspartokinase (or Aspartate kinase) is an
enzymethat catalyzes the phosphorylationof the amino acid aspartate. This reaction is the first step in the biosynthesisof three essential amino acids: methionine, lysine, and Threonine, known as the "aspartate family". The genefor aspartkinase is present only in microorganisms and plants; it is not present in animals, who must obtain aspartate-family amino acids in their diet.
E. coli, aspartokinase is present as three independently regulated isozymes, each of which is specific to one of the three downstream biochemical pathways. This allows the independent regulation of the rates of methionine, lysine, and threonine production. The forms that produce threonine and lysine are subject to feedback inhibition and all three can be repressed at the level of gene expressionby high concentrations of their end products. [cite journal|author=Voet D, Voet JG.
year= 2004|title=Biochemistry 3rd ed. Wiley: Hoboken, NJ.|volume=1|pmid=16729065|doi=10.1038/msb4100040|journal=Molecular Systems Biology|pages=E1] . Absence from animals makes these enzymes key targets for new herbicides and biocides and for improvements in nutritional value of crops. [cite journal|author=Viola RE.|journal=Acc Chem Res.|year= 2001|vol=34|title=The central enzymes of the aspartate family of amino acid biosynthesis|pmid=11352712|pages=339–49|doi=10.1021/ar000057q|volume=34]
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aspartokinase — Enzyme that phosphorylates L aspartate to produce aspartyl phosphate … Dictionary of molecular biology
aspartokinase — as·par·to·kin·ase (ə spär tō kīʹnās) n. An enzyme that catalyzes aspartic acid phosphorylation by ATP. [aspartic acid + kinase.] * * * … Universalium
aspartokinase — noun An enzyme that catalyzes the phosphorylation of the amino acid aspartate, the first step in the biosynthesis of three essential amino acids: methionine, lysine, and threonine … Wiktionary
aspartokinase — as·par·to·ki·nase ə .spärt ō kī .nās, .nāz n an enzyme that catalyzes the phosphorylation of aspartic acid by ATP … Medical dictionary
aspartokinase — as·par·to·kinase … English syllables
aspartokinase — əˌspärd.ōˌ noun Etymology: aspartic acid + o + kinase : an enzyme that catalyzes the phosphorylation of aspartic acid by ATP … Useful english dictionary
metabolism — /meuh tab euh liz euhm/, n. 1. Biol., Physiol. the sum of the physical and chemical processes in an organism by which its material substance is produced, maintained, and destroyed, and by which energy is made available. Cf. anabolism, catabolism … Universalium
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