title: A synthetic endopeptidase substrate hydrolyzed by the bovine lens neutral proteinase preparation.
abstract: Lens neutral proteinase is thought to exhibit primarily endopeptidase activity. We have identified a synthetic endopeptidase substrate which is hydrolyzed by the bovine lens neutral proteinase preparation. Among 11 fluoro- and chromogenic endopeptidase substrates, only carbobenzoxy-glycylglycyl-L-leucyl-p-nitroanilide is effectively hydrolyzed. The activity hydrolyzing this substrate co-elutes with neutral proteinase activity upon gel filtration and specifically attacks the leucyl-p-nitroaniline bond. Optimal hydrolysis of the synthetic substrate is at neutral pH and high temperature (53 degrees C), analogous to the alpha-crystallin protein substrate obtained from lens. The rate of hydrolysis of the synthetic substrate increased proportionally with temperature between 20 and 60 degrees C, in contrast to alpha-crystallin. The rate of hydrolysis was linear for at least 1 h at 37 degrees C and there was no evidence of enzyme activation at high temperature.
mesh_terms: D000818:Animals; D002417:Cattle; D002850:Chromatography, Gel; D010450:Endopeptidases / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007908:Lens, Crystalline / Q000201:enzymology*; D008666:Metalloendopeptidases; D009842:Oligopeptides / Q000378:metabolism*; D013696:Temperature; D013997:Time Factors
chemical_list: D009842:Oligopeptides; C037286:benzyloxycarbonylglycyl-glycyl-leucine-4-nitroanilide; D010450:Endopeptidases; C042365:lens neutral proteinase; D008666:Metalloendopeptidases