[Catalytic mechanism of dipeptidyl-peptidase IV].
Dipeptidyl-peptidase IV isolated from pig kidney microsomes catalyses hydrolysis in a number of dipeptidylaryl-amides of types L-AS-L-Ala-R and L-AS-L-Pro-R. Kinetic studies involving two competing substrates suggest the probable existence of a catalytic centre for both groups of substrates. The speed-determining steps in enzymatic hydrolysis differ in the order L-AS-L-Pro-R and L-AS-L-Ala-R. The secondary enzymatic deuterium-isotopic effects in the hydrolysis of L-Ala-L-Ala-2-d1-pNA are fixed at KHM/KDM = 1.24 and VHmax/VDmax = 1.27. The existence of an acyl-enzyme mechanism is considered likely.
D000818:Animals; D004151:Dipeptides; D010450:Endopeptidases / Q000378:metabolism*; D007668:Kidney / Q000201:enzymology; D007700:Kinetics; D008861:Microsomes / Q000201:enzymology; D013379:Substrate Specificity; D013552:Swine
D004151:Dipeptides; D010450:Endopeptidases
Beiträge zum Katalysemechanismus der Dipeptidyl-Peptidase. IV.