A possible role for oxygen inactivation in the regulation of amidophosphoribosyltransferase activity in mammalian cells

Abstract

Human and other mammalian forms of ATase, including the Chinese hamster enzyme, are oxygen-sensitive enzymes and human ATase, like the enzyme from B. subtilis, is an iron-sulfur protein. When protein synthesis is inhibited in cultured Chinese hamster cells, ATase activity is lost in an oxygen-dependent reaction. The hypothesis is developed that the sensitivity of ATase to oxygen inactivation controls the rate of degradation of this enzyme in mammalian cells, similar to the mechanism which has been demonstrated for regulation of ATase degradation in B. subtilis.