HISTOCHEMICAL AND BIOCHEMICAL-STUDIES ON GUANASE IN THE HUMAN AND RAT-KIDNEY

A specific antibody against purified human liver guanase was raised in rabbits. The antiserum formed a single precipitin line with human liver extracts, and completely inhibited the activity of the enzyme derived from human liver and kidney. Immunoblotting showed that the antibody bound only to the one protein band of liver and kidney guanase activity. In immunohistochemical studies, the DAB (3,3'-diaminobenzidine tetrahydrochloride)-reaction with this antibody was positive in the same locations as the histochemical guanase reaction. Moreover, biochemical data of enzymic activity in nephron segments of the rat indicated that guanase activity was located in the proximal tubules. Thus, the DAB reaction appeared to show the location of guanase itself. This immunohistochemical procedure for detection of guanase should useful in clinical studies on this enzyme.