1994 Volume 57 Issue 4 Pages 291-298
Age-associated changes in the activity of N-acetyl-β-D-glucosaminidase (NAGase), its enzyme properties and its isozyme pattern were examined using extract from the renal cortex and the medulla of senescence accelerated mice (SAMP8//Odu) at 7, 17, 27 and 37 weeks of age. Age-matched SAMR1/Odu (R strain) mice were used as controls. NAGase activity increased gradually up to 27 weeks of age in both the renal cortex and medulla of the P strain, and this increase was more pronounced in the renal cortex than in the renal medulla. Age-associated changes in the optimal pH, heat stability and the effect of additional compounds on the NAGase were different in both the renal cortex and medulla for the two strains. The NAGase of both the renal cortex and the medulla was separated by isoelectric focusing into four peaks for the two strains. In the renal cortex of the P strain there was a marked increase in the ratio peak I together with a decrease in peak II.
We propose that these changes are closely associated with senescence and may cause structural alterations of the acidic isozyme.
