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Blue‐light reactivation of spinach nitrate reductase inactivated by acetylene or cyanide. Effects of flavins and oxygen
Author(s) -
G. Mauriño Sofia,
A Maria,
Aparicio Pedro J.,
Maldonado José M.
Publication year - 1983
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1983.tb02761.x
Subject(s) - flavin group , nitrate reductase , photolyase , spinacia , chemistry , cyanide , nitrate , photochemistry , peroxidase , reductase , biochemistry , enzyme , inorganic chemistry , organic chemistry , dna repair , chloroplast , gene
Nitrate reductase (NADH: nitrate oxidoreductase, EC 1.6.6.1) of spinach ( Spinacia oleracea L.) leaves, inactivated in vitro by acetylene, was reactivated by irradiation with blue light. Red + infrared, green or white light of the same irradiance were less effective. The dehydrogenase activity of the nitrate reductase complex was not required for pliotoreactivation. Photoreactivation of cyanide‐inactivated nitrate reductase was greatly enhanced by the addition of 1 and 20 μ of either FMN or FAD; however, flavins showed a much smaller stimulatory effect on photoreactivation of acetylene‐inactivated enzyme. The effect of flavins was higher under anaerobic conditions. This might imply the direct ievolvement of excited flavins in the photoreactivation mechanism. Besides promoting photoreactivation, blue light irradiation led simultaneously to a gradual inactivation of the enzyme especially under air and 20 μ FMN, eventually abolishing the recovered activity of the enzyme.