Editing Aspartate transaminase (section)

== Function ==
Aspartate transaminase catalyzes the interconversion of [[aspartate]] (Asp) and [[α-ketoglutarate]] to [[oxaloacetate]] and [[glutamate]] (Glu):

: L-aspartate + α-ketoglutarate ↔ oxaloacetate + L-glutamate

[[File:Aspartate aminotransferase reaction.png|class=skin-invert-image|thumb|450px|Reaction catalyzed by aspartate aminotransferase]]

As a prototypical transaminase, AST relies on PLP (Vitamin B6) as a cofactor to transfer the amino group from aspartate or glutamate to the corresponding [[ketoacid]]. In the process, the cofactor shuttles between PLP and the [[pyridoxamine phosphate]] (PMP) form.<ref name="pmid6143829">{{Cite journal |vauthors=Kirsch JF, Eichele G, Ford GC, Vincent MG, Jansonius JN, Gehring H, Christen P |date=April 1984 |title=Mechanism of action of aspartate aminotransferase proposed on the basis of its spatial structure |journal=Journal of Molecular Biology |volume=174 |issue=3 |pages=497–525 |doi=10.1016/0022-2836(84)90333-4 |pmid=6143829}}</ref> The amino group transfer catalyzed by this enzyme is crucial in both amino acid degradation and biosynthesis. In amino acid degradation, following the conversion of α-ketoglutarate to glutamate, glutamate subsequently undergoes oxidative deamination to form [[ammonium]] ions, which are excreted as [[urea]]. In the reverse reaction, aspartate may be synthesized from oxaloacetate, which is a key intermediate in the [[citric acid cycle]].<ref name="Biochemistry">{{Cite book |title=Biochemistry |vauthors=Berg JM, Tymoczko JL, Stryer L |publisher=W.H. Freeman |year=2006 |isbn=978-0-7167-8724-2 |pages=656–660}}</ref>