Comparison of alanine aminopeptidase activities in Heterodera glycines and Caenorhabditis elegans

Abstract

AbstractAminopeptidases in whole body homogenates of Caenorhabditis elegans and Heterodera glycines were detected using a colorimetric assay with a series of seven aminoacyl p-nitroanilide substrates. Enzyme properties evaluated included substrate preference and stability in response to metal salts, alcohols and storage. The preferred substrate for both species was Ala-pNA, but C. elegans had a much broader substrate range than H. glycines. All substrates were more active in C. elegans than in H. glycines homogenates, except Pro-pNA which was three times more active than in H. glycines. Ca 2+, Mg 2+ and Zn 2+ inhibited C. elegans activity in a dose responsive manner but had little effect on H. glycines aminopeptidase, and Co 2+ was mildly inhibitory in both species. Ethanol inhibited both C. elegans and H. glycines aminopeptidases but methanol inhibited only H. glycines and increased C. elegans activity. Heterodera glycines aminopeptidase was more stable at room temperature than C. elegans.