EVIDENCE FOR INCREASED ANIONIC ARGINASE ACTIVITY IN PIG ENTEROCYTES DURING DEVELOPMENT

We have recently reported that the flux of L-arginine through arginase in enterocytes is increased in weaned pigs when compared with sucklin g animals (Blachier et al. 1993, Fur. J. Biochem. 216, 109-117). The a im of the present study was to characterize arginase activities at bot h stages of development. Enterocytes isolated from suckling animals we re found to possess an anionic (50%) and a non-anionic (50%) form of a rginase as judged from activities recovered from DEAE-cellulose ion ex change chromatography. In enterocytes isolated from weaned animals, an ionic arginase was the major form representing 89% of arginase activit y. This isoform is characterized by increased affinity for L-arginine (2 fold) and increased maximal velocity (39 fold) when compared with t he anionic form originating from suckling piglet enterocytes. In concl usion, our data demonstrate that pig enterocytes are equipped with at least 2 isoforms of arginase and that anionic form of arginase activit y appeared to be mainly responsible for the capacity of weaned pig ent erocytes to catabolize L-arginine.