Aspartate kinase

Aspartate kinase (aspartokinase, aspartic 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.

Aspartate kinase
Identifiers
EC number2.7.2.4
CAS number9012-50-4
Databases
IntEnzIntEnz view
BRENDABRENDA entry
ExPASyNiceZyme view
KEGGKEGG entry
MetaCycmetabolic pathway
PRIAMprofile
PDB structuresRCSB PDB PDBe PDBsum

In Escherichia 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 expression by high concentrations of their end-products.[1] Absence from animals makes these enzymes key targets for new herbicides and biocides and for improvements in nutritional value of crops.[2]

This protein may use the morpheein model of allosteric regulation.[3]

References
  1. Church GM (2004). "The personal genome project". Molecular Systems Biology. 1 (1): 2005.0030. doi:10.1038/msb4100040. PMC 1681452. PMID 16729065.
  2. Viola RE (May 2001). "The central enzymes of the aspartate family of amino acid biosynthesis". Accounts of Chemical Research. 34 (5): 339–49. doi:10.1021/ar000057q. PMID 11352712.
  3. Selwood T, Jaffe EK (March 2012). "Dynamic dissociating homo-oligomers and the control of protein function". Archives of Biochemistry and Biophysics. 519 (2): 131–43. doi:10.1016/j.abb.2011.11.020. PMC 3298769. PMID 22182754.


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