Premium
Characterization and Regulatory Properties of Glucose‐6‐Phosphate Dehydrogenase from Black Gram ( Phaseolus mungo )
Author(s) -
ASHIHARA HIROSHI,
KOMAMINE ATSUSHI
Publication year - 1976
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.1399-3054.1976.tb05027.x
Subject(s) - dehydrogenase , glucose 6 phosphate dehydrogenase , pentose phosphate pathway , enzyme , biochemistry , pyrophosphate , phosphate , chemistry , ammonium , phaseolus , biology , glycolysis , botany , organic chemistry
Glucose‐6‐phosphate dehydrogenase (E.C. 1.1.1.49) was partially purified by fractionation with ammonium sulfate and phosphocellulose chromatography. The K m value for glucose‐6‐phosphate is 1.6 × 10 −4 and 6.3 × 10 −4 M at low (1.0–6.0 × 10 −4 M ) and high (6.0–30.0 × 10 −4 M ) concentrations of the substrate, respectively. The K m value for NADP + is 1.4 × 10 −5 M . The enzyme is inhibited by NADPH, 5‐phosphoribosyl‐1‐pyrophosphate, and ATP, and it is activated by Mg 2+ , and Mn 2+ . In the presence of NADPH, the plot of activity vs. NADP + concentration gave a sigmoidal curve. Inhibition of 5‐phosphoribosyl‐1‐pyrophosphate and ATP is reversed by Mg 2+ or a high pH. It is suggested that black gram glucose‐6‐phosphate dehydrogenase is a regulatory enzyme of the pentose phosphate pathway.