Substrate analysis of homoserine acyltransferase from Bacillus cereus.
Substrate specificity within the family of enzymes designated as homoserine transsuccinylases is variable, with some organisms utilizing succinyl-CoA and other organisms utilizing acetyl-CoA. In this study it is shown that the enzyme from Bacillus cereus uses acetyl-CoA as its acyl donor, but its catalytic rate is significantly lower than other HTS family members. BcHTS is inactivated by both iodoacetamide and diethyl pyrocarbonate and the enzyme can be partially protected from inactivation by the presence of succinyl-CoA. This leads to the conclusion that BcHTS can bind both acetyl-CoA and succinyl-CoA and suggests that it may represent an intermediate between the succinate-transferring HTS family members and the acetate-transferring HTS family members. The B. cereus enzyme was unable to rescue growth of an Escherichia coli strain lacking a functional transsuccinylase, however.
Department of Chemistry and Biochemistry, George Mason University, 10900 University Blvd, Manassas, VA 20110, USA.
Katharine
K
Ziegler
Muzaffar
M
Yusupov
Barney
B
Bishop
Timothy L
TL
Born
D001409:Bacillus cereus / Q000201:enzymology*; D003001:Cloning, Molecular; D004047:Diethyl Pyrocarbonate / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D006714:Homoserine / Q000737:chemistry / Q000378:metabolism; D051082:Homoserine O-Succinyltransferase / Q000302:isolation & purification / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007460:Iodoacetamide / Q000494:pharmacology; D007700:Kinetics; D008715:Methionine / Q000378:metabolism; D050505:Mutant Proteins / Q000378:metabolism; D009596:Nitrophenols / Q000494:pharmacology; D013379:Substrate Specificity / Q000187:drug effects
D050505:Mutant Proteins; D009596:Nitrophenols; D006714:Homoserine; C008642:4-nitrophenyl acetate; D008715:Methionine; D051082:Homoserine O-Succinyltransferase; D004047:Diethyl Pyrocarbonate; D007460:Iodoacetamide