Metabolism of NAD⁺ in Nuclei of Saccharomyces cerevisiae during Stimulation of Its Biosynthesis by Nicotinamide

T. G. Gulyamova^*, D. M. Ruzieva, S. M. Nasmetova, M. R. Shakirzyanova, and A. M. Kerbalaeva

Institute of Microbiology, Uzbekistan Academy of Sciences, ul. Abdully Kodiry 7B, Tashkent, 700128 Uzbekistan; fax: (998-712) 417-129; E-mail: imbasru@uzsci.net

^* To whom correspondence should be addressed.

Received December 13, 2000; Revision received May 18, 2001

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The activities of nuclear enzymes involved in NAD⁺ metabolism in Saccharomyces cerevisiae strain 913a-1 and its mutant 110 previously selected as an NAD⁺ producer were investigated. The presence of extracellular nicotinamide increased the total NAD⁺ pool in the cells and increased [³H]nicotinic acid incorporation; however, NAD⁺ concentration in isolated nuclei decreased slightly. The stimulating effect of nicotinamide on intracellular synthesis of NAD⁺ correlated with increases in ADP-ribosyl transferase, NAD⁺-pyrophosphorylase, and NAD⁺ase activities.

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KEY WORDS: NAD⁺, NAD⁺-glycohydrolase, NAD⁺-pyrophosphorylase, ADP-ribose, ADP-ribosyl transferase

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