Identification of the rate-limiting step in serine proteinases from the effect of temperature on steady-state kinetics.
The effect of temperature on the steady-state kinetics of porcine pancreatic elastase can be used to determine whether acylation or deacylation is the rate-limiting step in catalysis. If acylation is rate-limiting, kcat and kcat/Km will show the same temperature dependence. If deacylation is rate-limiting, kcat will show a greater temperature dependence than kcat/Km. The temperature dependence of the steady-state kinetic parameters of t-Boc-Ala-Ala-Pro-Ala p-nitroanilide and N-acetyl-Ala-Ala-alpha-Aza-Ala p-nitrophenyl ester have been determined and are consistent with this prediction.
Fitzpatrick
P F
PF
Department of Biochemistry and Biophysics, Texas A & M University, College Station 77843.
D000215:Acylation; D000818:Animals; D002384:Catalysis; D007700:Kinetics; D009842:Oligopeptides / Q000378:metabolism; D010179:Pancreas / Q000201:enzymology*; D010196:Pancreatic Elastase / Q000378:metabolism*; D013552:Swine; D013696:Temperature
C059198:N-acetyl-alanyl-alanyl-2-aza-alanyl 4-nitrophenyl ester; C059199:N-tert-butoxycarbonylalanyl-alanyl-prolyl-alanyl 4-nitroanilide; D009842:Oligopeptides; D010196:Pancreatic Elastase