IMMUNOELECTROPHORETIC DETERMINATION OF NITRATE REDUCTASE IN NEUROSPORA-CRASSA

Highly selective and sensitive methods for determining nitrate reductase levels independent of any expression of its enzymatic activity have been developed, based on immunoelectrophoretic procedures. Specific antisera raised against Neurospora crassa NADPH-nitrate reductase inhibited the overall NADPH-nitrate reductase activity of this enzyme as well as partial activities of the electron transfer process associated with the nitrate reductase reaction. Three immunological techniques were employed to detect the presence of nitrate reductase-related protein in various Neurospora extracts: (i) a protection against inhibition assay, (ii) rocket immunoelectrophoresis, and (iii) crossed immunoelectrophoresis. These three methods were then applied to an analysis of nitrate reductase gene expression in the nit mutants of N. crassa. © 1979.