Demonstration in vitro of two intracellular inactivators of nitrate reductase from Neurospora

Two different inactivators of nitrate reductase have been found in cell free preparations of Neurospora. The first (Inactivator I) is very active at pH 9, is inhibited by disodium ethylene diamine tetraacetate (EDTA) and is present in all mycelia incubated under all conditions tested; the second (Inactivator II) is very active at pH 5, is repressed by ammonia or by a metabolic product of ammonia and derepressed by nitrogen starvation, cannot be …