A Prolyl Endopeptidase of Sarcophaga peregrina (Flesh Fly): Its Purification and Suggestion for Its Participation in the Differentiation of the Imaginal Discs

Abstract

A prolyl endopeptidase that hydrolyses Suc-Gly-Pro-MCA (Suc, succinyl; MCA, methylcoumaryl-7-amide) was purified to near homogeneity from NIH-Sape-4 cells derived from the flesh fly (Sarcophaga peregrina). The molecular mass of the purified enzyme was 84 kDa, and its activity was inhibited almost completely by 1mM diisopropyl fluorophosphate (DFP). Immunoblotting and DFP-labeling experiments revealed that the leg imaginal discs of Sarcophaga contained this enzyme as a major serine proteinase. This prolyl endopeptidase is suggested to be involved in the differentiation of imaginal discs, because 2mM DFP and 0.1mM N-benzyloxycarbonyl-thioprolyl-thioprolynal-dimethylacetal (ZTTA), a specific inhibitor for prolyl endopeptidase, inhibited differentiation of the imaginal discs from the eversion to the elongation stage.