title: Specificity of prolyl endopeptidase.
abstract: A series of tetrapeptides, Cbz(Bz)-Gly-X-Leu-Gly, were synthesized and the kinetic parameters, kcat and kcat/Km, determined for their hydrolyses by prolyl endopeptidase from Flavobacterium. The peptides with X = N-Me-Ala, Sar and Ala as well as the standard substrate (X = Pro) were found to be good substrates, while those with X = alpha-aminobutyryl, Hyp, Ser and Gly were poor substrates, and those with X = pipecolyl, alpha-aminoisobutyryl, N-Me-Val, N-Me-Leu, Hyp(O-Bzl) and Ser(O-Bzl) were not cleaved at all. These results suggest that the specificity-determining site or S1 subsite of the enzyme is designed to fit exactly the proline residue of the substrate with allowance for the residues carrying substituents at the N and/or C alpha which must not exceed the size of the pyrrolidine ring of proline.
mesh_terms: D001665:Binding Sites; D010450:Endopeptidases / Q000378:metabolism*; D005417:Flavobacterium / Q000201:enzymology*; D007700:Kinetics; D000085822:Prolyl Oligopeptidases; D012697:Serine Endopeptidases; D013379:Substrate Specificity
chemical_list: D010450:Endopeptidases; D012697:Serine Endopeptidases; D000085822:Prolyl Oligopeptidases