D-Aspartic Acid in Aged Mouse Skin and Lens

Abstract

D-aspartic acid (D-Asp) was detected in the skin and lens from naturally aged mice. An analysis of the amino acid composition indicated that D-Asp did not derive from collagen. An immnunological analysis using Oucterlony''s agar diffusion method also confirmed that the protein containing D-Asp was not a serum protein. The process producing D-Asp is regarded as one other than racemization because the life span of mice is not long enough to permit D-Asp by racemization. Continuous low-dose-rate gamma-irradiation (37R per day) for 102 to 112 days did not increase significantly the amount of D-Asp in skin and lens of mice.