Degradation of uric acid to urea and glyoxylate in peroxisomes.

The distribution of enzymes involved in purine degradation in fish and crustaceous liver was examined by centrifugation in a sucrose density gradient. In mackerel, yellow mackerel, and prawn liver and mantis club hepatopancreas, uricase and allantoinase were located only in the peroxisomes and in the soluble fraction from broken peroxisomes, and allantoicase was located only in the peroxisomes. Uricase and allantoinase seem to be located in the peroxisomal matrix and allantoicase in the peroxisomal membrane. Adenase, guanase, and xanthine oxidase were present only in the soluble fraction of mackerel liver.