Inherited differences in mouse kidney carnosinase activity.

Carnosinase is a peptidase which cleaves B-alanyl-L-histidine (carnosine) and closely related dipeptides. Its activity in kidney cytosol of various mouse strains varies more than 50-fold. The highest activity occurs in random-bred CD-1 and inbred NZB/BINJ mice, while it is barely detectable in BALB/cJ, C57BL/6J, and AU/SsJ among others. Carnosinase is immunologically and enzymologically identical in all high-activity strains. This is the first report of quantitative interstrain differences in carnosinase activity. No other peptidase activity has been reported which exhibits the same strain distribution shown here. In matings and backcrosses between the NZB/BINJ and the BALB/cJ strains, the levels of kidney carnosinase activity in the progeny behave as a classical Mendelian trait.