Further studies on elastase and trypsin inhibitory activities in mammalian lenses

Elastase and trypsin inhibitory capacities increased significantly on heat treatment of the lens extract for 15 min at 60 degrees C in human infant (mean increase 290 and 335%), human adult (130 and 245%), ovine (90 and 140%), and bovine (70 and 90%) lenses. No increase was observed in human cataractous lenses. Preincubation with target enzymes in the absence of substrate abolished the antitryptic activity in lenses whereas antielastase activity was more resistant. No decrease in antielastase activity in human adult and cataractous lenses was observed on 15-min preincubation whereas about 50% of activity was abolished in human infant lenses. The differences were attributed to the changes in the levels of endogenous proteinases and proenzymes during cataractogenesis and aging.