The utilization of alanine, glutamic acid, and serine as amino acid substrates for glycine N-acyltransferase.
The conjugation of benzoyl-CoA with the aliphatic and acidic amino acids by glycine N-acyltransferase, as well as the amides of the latter group, was investigated. Bovine and human liver benzoyl-amino acid conjugation were investigated using electrospray ionization tandem mass spectrometry (ESI-MS-MS). Bovine glycine N-acyltransferase catalyzed conjugation of benzoyl-CoA with Gly (Km(Gly) = 6.2 mM), Asn (Km(Asn) = 129 mM), Gln (Km(Gln) = 353 mM), Ala (Km(Ala) = 1573 mM), Glu (Km(Glu) = 1148 mM) as well as Ser in a sequential mechanism. In the case of the human form, conjugation with Gly (Km(Gly) = 6.4 mM), Ala (Km(Ala) = 997 mM), and Glu was detected. The presence of these alternative conjugates did not inhibit bovine glycine N-acyltransferase activity significantly. Considering the relatively low levels at which these conjugates are formed, it is unlikely that they will have a significant contribution to acyl-amino acid conjugation under normal conditions in vivo. However, their cumulative contribution to acyl-amino acid conjugation under metabolic disease states may prove to have a useful contribution to detoxification of elevated acyl-CoAs.
van der Westhuizen
F H
FH
School for Chemistry and Biochemistry, Potchefstroom University for Christian Higher Education, South Africa.
Pretorius
P J
PJ
Erasmus
E
E
D000217:Acyltransferases / Q000302:isolation & purification / Q000378:metabolism*; D000409:Alanine / Q000378:metabolism*; D000818:Animals; D002417:Cattle; D018698:Glutamic Acid / Q000378:metabolism*; D005998:Glycine / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D012694:Serine / Q000378:metabolism*
D018698:Glutamic Acid; D012694:Serine; D000217:Acyltransferases; C020680:glycine acyltransferase; D000409:Alanine; D005998:Glycine