title: Similarities of the substrate cleavage catalyzed by proline specific endopeptidase and dipeptidyl peptidase IV.
abstract: 16 substrates of the types succinyl-alanyl-alanine-pX-anilide, and succinyl-alanyl-proline-pX anilide having different substituents in para-position of the aryl residue were synthesized and characterized. The influence of electronic as well as hydrophobic substituent constants, sigma and pi, on the hydrolysis of the substrates catalyzed by the enzyme Proline Specific Endopeptidase (PSE) has been investigated. In the Hansch approach, the catalytic constants lg kcat and lg (kcat/KM) of succinyl-alanyl-alanine-pX-anilides hydrolyzed by PSE correlate significantly with electronic substituent constants sigma, whereas no correlation in the case of succinyl-alanyl-proline-pX-anilides. The intercorrelation of the constants of the former substrates with corresponding data from Dipeptidyl Peptidase IV (DP IV) catalyzed hydrolysis of alanyl-alanine-pX-anilides suggest that both enzymes act by similar catalytic mechanism.
mesh_terms: D055598:Chemical Phenomena; D002627:Chemistry, Physical; D018819:Dipeptidyl Peptidase 4; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000378:metabolism*; D010450:Endopeptidases / Q000378:metabolism*; D005417:Flavobacterium / Q000201:enzymology; D006868:Hydrolysis; D007700:Kinetics; D000085822:Prolyl Oligopeptidases; D012697:Serine Endopeptidases; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
chemical_list: D010450:Endopeptidases; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; D018819:Dipeptidyl Peptidase 4; D012697:Serine Endopeptidases; D000085822:Prolyl Oligopeptidases