Proteases in the Emory mouse cataract.

Exopeptidases identified as dipeptidyl peptidase III and leucine aminopeptidase, and an endopeptidase, prolyl endopeptidase, were found in the Emory Mouse cataract and the Cataract Resistant mouse lens extracts. The specific activity measured on Arg-Arg-2-NNap for DPP III and the hydrolysis of Boc-Arg-Pro-2-NNap for prolyl endopeptidase were higher in the Emory Mouse cataractous lens extract. A relatively high rate of hydrolysis of the beta-naphthylamide of leucine aminopeptidase was present in both mouse categories; however, the Cataract Resistant mouse lens had approximately double the protease activity of the Emory Mouse cataract.

Proteases in human lenses and their possible significance.

Proteases identified as exopeptidases including dipeptidyl II and III, phenylalanine, leucine, methionine, lysine and alanine aminopeptidases, and prolyl endopeptidase were found in extracts of human fetal lenses. Previous data from normal adult lenses were included for comparison. Except for prolyl endopeptidase and dipeptidyl peptidase II, all protease activities were lower in fetal lenses.