Pyridine nucleotide specificity and other properties of purified nitrate reductase fromChlorella variegata

✍ Scribed by C. R. Hipkin; B. A. Al-Bassam; P. J. Syrett

• Publisher: Springer-Verlag
• Year: 1979
• Tongue: English
• Weight: 415 KB
• Volume: 144
• Category: Article
• ISSN: 0032-0935
• DOI: 10.1007/bf00387262

✦ Synopsis

Nitrate reductase (NR) (EC 1.6.6.2.) from Chlorella variegata 211/10d has been purified by blue sepharose affinity chromatography. The enzyme can utilise N A D H or N A D P H for nitrate reduction with apparent Km values of 11.5 laM and 14.5 gM, respectively. Apparent Km values for nitrate are 0.13 mM ( N A D H -N R ) and 0.14 mM (NADPH-NR). The diaphorase activity of the enzyme is inhibited strongly by parachtoromercuribenzoic acid; N A D H or N A D P H protects the enzyme against this inhibition. N R proper activity of the enzyme is partially inactive after extraction and may be activated after the addition of ferricyanide. The addition of NAD(P)H and cyanide causes a reversible inactivation of the N R proper activity although preincubation with either N A D H or N A D H and ADP has no significant effect.