AMP makes native snake muscle fructose-1,6-bisphosphatase to an alkaline enzyme  

作　　者：赵辅昆 徐松琴 杜立林 许根俊 

机构地区：[1]Shanghai Institute of Biochemistry, Chinese Academy of Sciences, Shanghai 200031, China

出　　处：《Science China(Life Sciences)》2000年第1期1-7,共7页中国科学（生命科学英文版）

摘　　要：A substance in the crude preparation of NADP+ has been found, which activates snake muscle fructose-1,6-bisphosphatase at pH 9.2 and inhibits the enzyme at pH 7.5. After isolation and extensive characterization, the substance has been determined to be AMP. The activation depends on the concentrations of Mg2+ and could be observed only at concentrations above 1 mmol/L. In the presence of AMP, snake muscle fructose-1,6-bisphosphatase resembles an alkaline enzyme. Kinetic studies indicate that AMP and Mg2+ competitively regulate the activity of the enzyme. AMP releases the inhibition of Mg2+ at high concentration at alkaline pH. It has been reported that fructose-1,6-bisphosphatase with a pH optimum in the alkaline region is caused by limited proteolysis. AMP is also able to make fructose-1,6-bisphosphatase to be an alkaline enzyme. This finding indicates that proteolysis may not be the only reason for shift of the optimum pH of fructose-1,6-bisphosphatase to alkaline side and it may imply some significance in physiological regulation.A substance in the crude preparation of NADP+ has been found, which activates snake muscle fructose-1,6-bisphosphatase at pH 9.2 and inhibits the enzyme at pH 7.5. After isolation and extensive characterization, the substance has been determined to be AMP. The activation depends on the concentrations of Mg2+ and could be observed only at concentrations above 1 mmol/L. In the presence of AMP, snake muscle fructose-1,6-bisphosphatase resembles an alkaline enzyme. Kinetic studies indicate that AMP and Mg2+ competitively regulate the activity of the enzyme. AMP releases the inhibition of Mg2+ at high concentration at alkaline pH. It has been reported that fructose-1,6-bisphosphatase with a pH optimum in the alkaline region is caused by limited proteolysis. AMP is also able to make fructose-1,6-bisphosphatase to be an alkaline enzyme. This finding indicates that proteolysis may not be the only reason for shift of the optimum pH of fructose-1,6-bisphosphatase to alkaline side and it may imply some

关 键 词：Fructose-1 6-bisphosphatase AMP activation limited PROTEOLYSIS Mg2+ regulation. 

分 类 号：Q55[生物学—生物化学]