Problems of nitrogen catabolism in invertebrates

Abstract

A new method is described for the detection and estimation of small amts. of arginase; urea was estimated by the mano-metric method after incubation of tissue brei with arginine under standard conditions; the method is at least 100 times as sensitive as the earlier methods. Examination of a variety of invertebrates showed that arginase is much more widely distributed than has hitherto been supposed. A correlation between the arginase and the uric acid contents of the hepatopan-creases and nephridia respectively of a number of gastropods, suggests that arginase is concerned in the production of uric acid by members of this class. Thus in the elaboration both of urea and of uric acid, which represent the principal nitrogenous end-products of the non-sauropsid vertebrates and the gastropods respectively, the same enzyme, arginase, may be involved.