Site-directed Mutagenesis of Nitrate Reductase from Aspergillus nidulans

The regulation of nitrate reductase in the fungus Aspergillus nidulans.

Nitrate reductase induction by nitrate and repression by NH,+ has been studied extensively in the simple eukaryote Aspergillus nidulans (Pateman & Cove, 1967; Cove & Pateman, 1968). Wild-type cells grown on minimal medium, with 20m~-NaNO~ as the nitrogen source, rapidly lose nitrate reductase activity when transferred either to minimal medium without N (-N medium) or to minimal medium without C...

Characterization of ferredoxin:thioredoxin reductase modified by site-directed mutagenesis.

Ferredoxin:thioredoxin reductase (FTR) is a key regulatory enzyme of oxygenic photosynthetic cells involved in the reductive regulation of important target enzymes. It catalyzes the two-electron reduction of the disulfide of thioredoxins with electrons from ferredoxin involving a 4Fe-4S cluster and an adjacent active-site disulfide. We replaced Cys-57, Cys-87, and His-86 in the active site of S...

Characterization of ferredoxin:thioredoxin reductase (FTR) modified by site-directed mutagenesis

Characterization of the reduced nicotinamide adenine dinucleotide phosphate-nitrate reductase of Aspergillus nidulans.

The reduced nicotinamide adenine dinucleotide phosphate (NADPH)-nitrate oxidoreductase (EC 1.6.6.2) from Aspergillus nidulans was purified over 200-fold by use of salt fractionation, gel filtration, and ion-exchange chromatography. The purified enzyme was specific for NADPH and catalyzed reduction of nitrate, cytochrome c from isolated mitochondria of Aspergillus, and mammalian cytochrome c. An...

Kinetic studies of the induction of nitrate reductase and cytochrome c reductase in the fungus Aspergillus nidulans.

In an earlier paper (Cove, 1966) it was reported that the kinetics of appearance of nitrate reductase (NADPH-nitrate oxidoreductase, EC 1.6.6.3) on the addition of nitrate to a growing culture of Aspergillus nidulans were different in certain respects from those found for many Escherichia coli enzymes. When urea is used as an initial nitrogen source, a further difference is found: enzyme synthe...