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4-aminobutyrate---pyruvate transaminase (EC 2.6.1.96, aminobutyrate aminotransferase, gamma-aminobutyrate aminotransaminase, gamma-aminobutyrate transaminase, gamma-aminobutyric acid aminotransferase, gamma-aminobutyric acid pyruvate transaminase, gamma-aminobutyric acid transaminase, gamma-aminobutyric transaminase, 4-aminobutyrate aminotransferase, 4-aminobutyric acid aminotransferase, aminobutyrate transaminase, GABA aminotransferase, GABA transaminase, GABA transferase, POP2 (gene)) is an enzyme with systematic name 4-aminobutanoate:pyruvate aminotransferase. This enzyme is a type of GABA transaminase, which degrades the neurotransmitter GABA. The enzyme catalyses the following chemical reaction

(1) 4-aminobutanoate + pyruvate ${\displaystyle \rightleftharpoons }$ succinate semialdehyde + L-alanine

(2) 4-aminobutanoate + glyoxylate ${\displaystyle \rightleftharpoons }$ succinate semialdehyde + glycine

This enzyme requires pyridoxal 5'-phosphate.

Clinical significance

Phenylethylidenehydrazine, the active metabolite of phenelzine, inhibits gamma-aminobutyric acid transaminase and subsequently increases GABA concentrations in the central nervous system. This may contribute to the notable anxiolytic effects of phenelzine.

References

1. Van Cauwenberghe, O.R.; Shelp, B.J. (1999). "Biochemical characterization of partially purified gaba:pyruvate transaminase from Nicotiana tabacum". Phytochemistry. 52: 575–581. doi:10.1016/s0031-9422(99)00301-5.
2. Palanivelu R, Brass L, Edlund AF, Preuss D (July 2003). "Pollen tube growth and guidance is regulated by POP2, an Arabidopsis gene that controls GABA levels". Cell. 114 (1): 47–59. doi:10.1016/s0092-8674(03)00479-3. PMID 12859897.
3. Clark SM, Di Leo R, Dhanoa PK, Van Cauwenberghe OR, Mullen RT, Shelp BJ (2009). "Biochemical characterization, mitochondrial localization, expression, and potential functions for an Arabidopsis gamma-aminobutyrate transaminase that utilizes both pyruvate and glyoxylate". Journal of Experimental Botany. 60 (6): 1743–57. doi:10.1093/jxb/erp044. PMC 2671622. PMID 19264755.
4. Clark SM, Di Leo R, Van Cauwenberghe OR, Mullen RT, Shelp BJ (2009). "Subcellular localization and expression of multiple tomato gamma-aminobutyrate transaminases that utilize both pyruvate and glyoxylate". Journal of Experimental Botany. 60 (11): 3255–67. doi:10.1093/jxb/erp161. PMC 2718222. PMID 19470656.
5. McKenna KF, McManus DJ, Baker GB, Coutts RT (1994). "Chronic administration of the antidepressant phenelzine and its N-acetyl analogue: effects on GABAergic function". Journal of Neural Transmission. Supplementum. 41: 115–22. doi:10.1007/978-3-7091-9324-2_15. ISBN 978-3-211-82521-1. PMID 7931216.

External links

• 4-aminobutyrate---pyruvate+transaminase at the U.S. National Library of Medicine Medical Subject Headings (MeSH)

• Biology

• EC 2.6.1