Glucokinase of pea seeds.
1. Glucokinase (ATP : D-glucose 6-phosphotransferase, EC 2.7.1.2) was extracted from pea seeds and purified by fractionation with (NH4)2SO4 and chromatography on DEAE-cellulose and Sephadex. 2. The relative rates of phosphorylation of glucose, mannose and fructose (final concentration 5 mM) were 100, 64 and 11. 3. The Km for glucose of pea-seed glucokinase was 70 muM and the Km for mannose was 0.5 mM. The Km for fructose was much higher (30 mM). 4. Mg2+ ions were essential for activity. Mn2+ could partially replace Mg2+. 5. Enzyme activity was not inhibited by glucose 6-phosphate. A number of other metabolites had no effect on glucokinase activity. 6. Pea-seed glucokinase was inhibited by relatively low concentrations of ADP.
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D003300:Copper / Q000494:pharmacology; D005632:Fructose / Q000378:metabolism; D005941:Glucokinase / Q000302:isolation & purification / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D005958:Glucosephosphates / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D008358:Mannose / Q000378:metabolism; D008628:Mercury / Q000494:pharmacology; D012639:Seeds / Q000201:enzymology*
D005958:Glucosephosphates; D005632:Fructose; D000244:Adenosine Diphosphate; D003300:Copper; D000255:Adenosine Triphosphate; D005941:Glucokinase; D008628:Mercury; D008274:Magnesium; D005947:Glucose; D008358:Mannose