Studies of the enzymes involved in nicotinamide adenine dinucleotide metabolism in Aspergillus niger

Sarma, DSR and Rajalakshmi, S and Sarma, PS (1964) Studies of the enzymes involved in nicotinamide adenine dinucleotide metabolism in Aspergillus niger. In: Biochimica et Biophysica Acta (BBA) - Specialized Section on Enzymological Subjects, 81 (2). pp. 311-322.

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Abstract

The enzyme nicotinamide amidase (nicotinamide amidohydrolase) was purified 57-fold from Aspergillus niger. The purified preparation was specific towards its substrate nicotinamide and did not deamidate NADP, NAD, NMN, N′-methyl nicotinamide, asparagine, glutamine, benzamide, α-naphthaleneamide and indoleacetamide. The asparagine, glutamine, benzamide, α-naphthaleneamide and indoleacetamide.vThe optimum pH was found to be 7.5. Temperature optimum was 40°. It had a Km value of 6.504 · 10−4 M towards nicotinamide. The enzyme exhibited Mg2+ ion requirement for its optimum activity. NAD-glycohydrolase (EC 3.2.2.5) was purified 109-fold from the mold. A. niger. The enzyme preparation was active only towards NAD and NADP and did not attack NMN, N′-methylnicotinamide and NADH. The Km value for NAD was found to be 7.693 · 10−6 M. The enzyme did not require any metal ion for its activity. It is suggested that A. niger will serve a better source for a large scale preparation of NAD-glycohydrolase than the Neurospora mold. The biological role of both NAD-glycohydrolase and nicotinamide amidase in the regulation of cellular NAD level has been discussed. It is, further, observed that NAD did not exert its feedback control on nicotinamide amidase at least in A. niger.

Item Type:	Journal Article
Publication:	Biochimica et Biophysica Acta (BBA) - Specialized Section on Enzymological Subjects
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Department/Centre:	Division of Biological Sciences > Biochemistry
Date Deposited:	24 May 2010 08:36
Last Modified:	19 Sep 2010 06:07
URI:	http://eprints.iisc.ac.in/id/eprint/28094

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