Catalytic properties of phosphoglucomutase from pea chloroplasts.
Electrophoretically homogeneous phosphoglucomutase (PGM) with specific activity of 3.6 units/mg protein was isolated from pea (Pisum sativum L.) chloroplasts. The molecular mass of this PGM determined by gel-filtration is 125 +/- 4 kD. According to SDS-PAGE, the molecular mass of subunits is 65 +/- 3 kD. The Km for glucose-1-phosphate is 18.0 +/- 0.5 microM, and for glucose-1, 6-diphosphate it is 33 +/- 0.7 microM. At glucose-1-phosphate and glucose-1,6-diphosphate concentrations above 0.5 and 0.2 mM, respectively, substrate inhibition is observed. The enzyme has optimum activity at pH 7.9 and 35 degrees C. Mg2+ activates the PGM. Mn2+ activates the enzyme at concentrations below 0.2 mM, while higher concentrations have an inhibitory effect. The activity of the PGM is affected by 6-phosphogluconate, fructose-6-phosphate, NAD+, ATP, ADP, citrate, and isocitrate.
Matasova
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LV
Department of Plant Physiology and Biochemistry, Voronezh State University, Voronezh, 394693, Russia. root@bc.vsu.ru
Popova
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TN
D002384:Catalysis; D002736:Chloroplasts / Q000201:enzymology*; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D018532:Pisum sativum / Q000201:enzymology*; D010733:Phosphoglucomutase / Q000378:metabolism*; D013379:Substrate Specificity; D013696:Temperature
D010733:Phosphoglucomutase