Effect of aging on rat tissue peptidase activities

Area of Science:

• Biochemistry
• Gerontology
• Molecular Biology

Background:

• Aging is associated with changes in peptidase and protease activity.
• Specific alterations in aged tissues remain incompletely understood, with varied reports on peptidase activity and peptide levels.
• Peptidases play crucial roles in regulating peptide homeostasis.

Purpose of the Study:

• To investigate age-related changes in the activity of specific peptidases in various rat tissues.
• To characterize the differential impact of aging on peptidase activity across different organs.
• To correlate observed peptidase activity changes with known peptide level alterations during aging.

Main Methods:

• Assay of prolyl endopeptidase, pyroglutamyl peptidase I, puromycin sensitive aminopeptidase, and aminopeptidase N activities.
• Use of beta-naphthylamine aminoacidic derivatives as substrates.
• Comparison of enzyme activities in young adult (3 months) and aged (18 and 22 months) rats across brain cortex, brain stem, liver, kidney, heart, and lung tissues.

Main Results:

• Reduced soluble prolyl endopeptidase activity observed in aged rat lungs.
• Decreased activity of soluble pyroglutamyl peptidase I in aged kidneys and soluble aminopeptidase N in aged hearts.
• Increased activity of particulate prolyl endopeptidase detected in the brain stem of aged rats.

Conclusions:

• Specific peptidases exhibit altered activity in various tissues during aging.
• These age-dependent peptidase activity changes in tissues like the lung, kidney, heart, and brain stem are significant.
• The findings suggest that these peptidases are key regulators of tissue peptide levels throughout the aging process.