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B6db activities: 2.6.1.81

2.6.1.81
Description Succinylornithine transaminase
Alternative names Succinylornithine aminotransferase;
N2-succinylornithine 5-aminotransferase;
AstC;
SOAT.
Catalyzed reaction N2-succinyl-L-ornithine + 2-oxoglutarate = N-succinyl-L-glutamate 5-semialdehyde + L-glutamate
Cofactor Pyridoxal-phosphate.
Comments Also acts on N2-acetyl-L-ornithine and L-ornithine, but more slowly.
In Pseudomonas aeruginosa, the arginine-inducible succinylornithine transaminase, acetylornithine transaminase (EC 2.6.1.11) and ornithine aminotransferase (EC 2.6.1.13) activities are catalysed by the same enzyme, but this is not the case in all species.

This is the third enzyme in the arginine succinyltransferase (AST) pathway for the catabolism of arginine.
This pathway converts the carbon skeleton of arginine into glutamate, with the concomitant production of ammonia and conversion of succinyl-CoA into succinate and CoA. The five enzymes involved in this pathway are EC 2.3.1.109 (arginine N-succinyltransferase), EC 3.5.3.23 (N-succinylarginine dihydrolase), EC 2.6.1.81 (succinylornithine transaminase), EC 1.2.1.71 (succinylglutamate-semialdehyde dehydrogenase) and EC 3.5.1.96 (succinylglutamate desuccinylase).
Of the five enzymes involved in arginine catabolism, this is the only one that is also involved in ornithine catabolism.

Known genes are very similar to EC 2.6.1.11 (Acetylornithine aminotransferase).
PDB 4ADB; 4ADD;
Organisms -Eubacteria
 

Family 

2.6.1.81 (7)
 
Links Enzyme (activities) 2.6.1.81
BRENDA (activities) 2.6.1.81
KEGG (pathways) 2.6.1.81
PLPMDB (PLP mutants) 2.6.1.81
 
References
 Newman J, Seabrook S, Surjadi R, Williams CC, Lucent D, Wilding M, Scott C, Peat TS. (2013) Determination of the structure of the catabolic N-succinylornithine transaminase (AstC) from Escherichia coli PLoS One. 8 e58298.

 Schneider BL, Kiupakis AK, Reitzer LJ. (1998) Arginine catabolism and the arginine succinyltransferase pathway in Escherichia coli J Bacteriol 180 4278-86.

 Itoh Y. (1997) Cloning and characterization of the aru genes encoding enzymes of the catabolic arginine succinyltransferase pathway in Pseudomonas aeruginosa J Bacteriol 179 7280-90.

Articles on 2.6.1.81
 
last changed 2014/03/20 11:36

B6db activities