AGE-INDUCED INCREASE OF LEUCINE-ENKEPHALIN ENZYME DEGRADATION IN HUMAN PLASMA

Possible age-induced variations of the hydrolysis of leucine enkephali n in the presence of plasma enzymes were studied by kinetic and chroma tographic techniques in a group of elderly individuals. Results obtain ed indicate that in elderly individuals the activity of enkephalin-deg rading plasma enzymes is greater than in the controls; ANOVA analysis of these data indicates that the dependency of the variation of hydrol ysis upon the two age groups is statistically significant. Increased s ubstrate hydrolysis, and a modified hydrolysis pattern, appear to be a ssociated with increased activity of the enzymes involved, and with di fferent distribution of the individual enzymes within each class, as w ell as with severely reduced activity of the low molecular weight plas ma inhibitors. The combination of these factors defines a characterist ic hydrolysis pattern for the elderly individuals, different from that found in the controls. (C) 1998 Elsevier Science Inc.