Induction and repression of nitrate reductase in Neurospora crassa.

Kinsky, Stephen C. (Washington University, St. Louis, Mo.). Induction and repression of nitrate reductase in Neurospora crassa. J. Bacteriol. 82:898-904. 1961.-Techniques are described for studying induced enzyme formation in Neurospora crassa. The effects of various parameters (time, pH, nitrate concentration, etc.) on the induction of nitrate reductase were investigated. It was demonstrated that NH(4) (+), which is the end product of the metabolic sequence initiated by nitrate reductase, repressed formation of the enzyme. Parallel to the formation of nitrate reductase there was an increase in reduced triphosphopyridine nucleotide (TPNH)-cytochrome c reductase activity. The relationship of these two activities to each other and to the constitutive TPNH-cytochrome c reductase present in noninduced mycelia is discussed.