The regulation of nitrate reductas enad catalase by amino acids in Neurospora crassa

Subramanian, KN and Padmanaban, G and Sarma, PS (1968) The regulation of nitrate reductas enad catalase by amino acids in Neurospora crassa. In: Biochimica et Biophysica Acta (BBA) - Enzymology, 151 (1). pp. 20-32.

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Abstract

The induction of nitrate reductase (NADPH:nitrate oxidoreductase, EC 1.6.6.3) by nitrate in Neurospora crassa and its control by amino acids have been studied. The growth-inhibitory amino acids, isoleucine and cysteine as well as the growth-promotory ones, glutamine, asparagine, arginine, histidine and NH4+, repress nitrate reductase effectively. Methionine, tryptophan, proline, aspartic acid and glutamic acid exert little control on nitrate reductase. The repression of nitrate reductase by cysteine, isoleucine, glutamine and asparagine is accompanied by inactivation of the enzyme present initially. The nitrate-induced NADPH-cytochrome c reductase (NADPH:cytochrome c oxidoreductase, EC 1.6.2.3) is also repressed by amino acids which control nitrate reductase, providing further evidence to show that these two enzyme activities may reside in the same protein. Catalase (H2O2:H2O2 oxidoreductase, EC 1.11.1.6) has been found to be induced subsequent to the induction of nitrate reductase by nitrate in N. crassa. The induction of catalase is probably by its substrate H2O2 which would be formed by the interaction of the flavine component of nitrate reductase with oxygen. The amino acids which control nitrate reductase, repress catalase also. The catalase level appears to be determined by the nitrate reductase activity of the mycelia.

Item Type:	Journal Article
Publication:	Biochimica et Biophysica Acta (BBA) - Enzymology
Publisher:	Elsevier Science
Additional Information:	Copy right of this article belongs to Elsevier Science.
Department/Centre:	Division of Biological Sciences > Biochemistry
Date Deposited:	14 May 2010 04:55
Last Modified:	19 Sep 2010 06:06
URI:	http://eprints.iisc.ac.in/id/eprint/27745

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