Propionyl-coenzyme A synthetases of Ralstonia solanacearum and Salmonella choleraesuis display atypical kinetics.
Propionyl-coenzyme A synthetases (PrpE) of Salmonella choleraesuis and Ralstonia solanacearum sharing 62% identity in amino acid sequence to each other were cloned, expressed in Escherichia coli and purified. Both enzymes catalyzed acetyl-, propionyl-, butyryl- and acrylyl-coenzyme A formation with the highest k(cat)/K(m) values for propionate. They displayed sigmoidal homotrophic autoactivation kinetics for propionate but not for the other acyl substrates tested. Besides, substrate inhibition kinetics was observed for co-substrates, i.e. ATP and CoA. Based on the kinetic data reported herein, the reaction mechanisms of the enzyme are discussed.
Rajashekhara
Eranna
E
Laboratory of Applied Microbiology, Marine Biotechnology Institute, 3-75-1 Heita, 026-0001, Iwate-ken, Kamaishi-shi, Japan. rajashekhara@mbio.jp
Watanabe
Kazuya
K
D000144:Acids, Acyclic / Q000737:chemistry / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism / Q000494:pharmacology; D003065:Coenzyme A / Q000378:metabolism / Q000494:pharmacology; D003066:Coenzyme A Ligases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D043368:Ralstonia solanacearum / Q000201:enzymology*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019779:Salmonella enterica / Q000201:enzymology* / Q000235:genetics; D013379:Substrate Specificity; D013696:Temperature
D000144:Acids, Acyclic; D011994:Recombinant Proteins; D000255:Adenosine Triphosphate; D003066:Coenzyme A Ligases; C068072:propionate - CoA ligase; D003065:Coenzyme A