兔骨骼肌中1,6-二磷酸葡萄糖合成的特异性

Specificity of glucose 1,6-bisphosphate synthesis in rabbit skeletal muscle.

Piatti E, Accorsi A, Piacentini M P, Fazi A

Institute of Biological Chemistry, Giorgio Fornaini, Urbino (PS), Italy.

Comp Biochem Physiol B. 1991;100(1):67-71. doi: 10.1016/0305-0491(91)90086-s.

Abstract

To compare glucose 1,6-bisphosphate synthesis in different types of cells, we partially purified (2000-fold) a glycerate 1,3 P2-dependent glucose 1,6-bisphosphate synthase from rabbit skeletal muscle. 2. In agreement with the results reported by others for mouse brain and pig skeletal muscle, the enzyme can be separated from bulk phosphoglucomutase (PGM) activity by DEAE-cellulose chromatography of crude cellular extract. This cannot be achieved on human hemolysates where glycerate 1,3-P2-dependent glucose 1,2-bisphosphate synthesis is displayed only by multifunctional PGM2 isoenzymes. 3. The Km values for glycerate 1,3-P2 (0.50 microM), glucose 1-phosphate (90 microM), Mg2+ (0.22 mM), and also pH optimum (7.8) and mol. wt (70,000) of the rabbit skeletal muscle enzyme are similar to those of the enzymes from mouse brain and human red blood cells, but they differ from those reported for the pig skeletal muscle enzyme.

摘要

为了比较不同类型细胞中1,6 -二磷酸葡萄糖的合成，我们从兔骨骼肌中部分纯化了（2000倍）一种依赖1,3 -二磷酸甘油酸的1,6 -二磷酸葡萄糖合酶。2. 与其他人报道的小鼠脑和猪骨骼肌的结果一致，通过对粗细胞提取物进行DEAE -纤维素色谱法，可以将该酶与大量磷酸葡萄糖变位酶（PGM）活性分离。而在人溶血产物中无法实现这一点，因为在人溶血产物中，仅多功能PGM2同工酶表现出依赖1,3 -二磷酸甘油酸的1,2 -二磷酸葡萄糖合成。3. 兔骨骼肌酶对1,3 -二磷酸甘油酸（0.50微摩尔）、1 -磷酸葡萄糖（90微摩尔）、Mg2 +（0.22毫摩尔）的Km值，以及最适pH（7.8）和分子量（70,000）与小鼠脑和人红细胞中的酶相似，但与报道的猪骨骼肌酶不同。