THE INHIBITORY EFFECT OF NITRITE, A STABLE PRODUCT OF NITRIC-OXIDE (NO) FORMATION, ON ARGINASE

Macrophages contain arginase and an inducible NO synthase, demonstrate d by using L-arginine, the common substrate, for production of both ni tric oxide and urea, Arginase was inhibited by nitrite, the stable end product of NO, This inhibition was non-competitive, and could not be explained by the reaction of nitrite with arginine, or by the irrevers ible covalent modification of arginase, or by the removal of Mn2+, a c ofactor of arginase.