| PURIFICATION AND KINETICS OF MOUSE LIVER FRUCTOSE 6-PHOSPHATE, 2-KINASE |
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| 作者姓名： | 李林 许根俊 |
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| 作者单位： | Shanghai Institute of Biochemistry，Academia Sinica，Shanghai Institute of Biochemistry，Academia Sinica |
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| 基金项目： | Project supported by the National Natural Foundation of China. |
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| 摘 要： | The mouse liver fructose 6-phosphate, 2-kinase was purified by ultracentrifugation, polyethylene glycol precipitation, and subsequently by chromatography on DEAE-Sephadex, Blue-Sepharose and phasphocellulose columnS. Gel filtration and SDS polyacrylamide electrophorcsis showed that the enzyme has a molecular weight of 110,000 with two identical subunits. Mg~(2+) is essential for its activity. The activation of the enzyme by Mg~(2+) showed a positive cooperativity. The substrate saturation curve for fructose 6-phosphate was sigmoidal and for ATP was hyperbolic. The K_m's for ATP increased with decrease in concentrations of fructose 6-phosphate indicating that the sequence for the substrates binding was in an ordered mechanism with respect to fructose 6-phosphate prior to ATP. An ionizable residue at the active site with pKa 9.5 was essential for the ATP binding and the pKa shifted to 9.8 after the binding of ATP.
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PURIFICATION AND KINETICS OF MOUSE LIVER FRUCTOSE 6-PHOSPHATE, 2-KINASE |
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| LI LIN AND XU GENJUN.PURIFICATION AND KINETICS OF MOUSE LIVER FRUCTOSE 6-PHOSPHATE, 2-KINASE[J].Science in China(Chemistry),1988(11). |
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| Authors: | LI LIN AND XU GENJUN |
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| Abstract: | The mouse liver fructose 6-phosphate, 2-kinase was purified by ultracentrifugation, polyethylene glycol precipitation, and subsequently by chromatography on DEAE-Sephadex, Blue-Sepharose and phasphocellulose columnS. Gel filtration and SDS polyacrylamide electrophorcsis showed that the enzyme has a molecular weight of 110,000 with two identical subunits. Mg~(2+) is essential for its activity. The activation of the enzyme by Mg~(2+) showed a positive cooperativity. The substrate saturation curve for fructose 6-phosphate was sigmoidal and for ATP was hyperbolic. The K_m's for ATP increased with decrease in concentrations of fructose 6-phosphate indicating that the sequence for the substrates binding was in an ordered mechanism with respect to fructose 6-phosphate prior to ATP. An ionizable residue at the active site with pKa 9.5 was essential for the ATP binding and the pKa shifted to 9.8 after the binding of ATP. |
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| Keywords: | fructose 6-phosphate 2-kinase cooperative binding fashion scheme of a mechanism |
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