Blumenfeld M L, Krisman C R
J Biol Chem. 1985 Sep 25;260(21):11560-6.
Two fractions of glycogen synthase were isolated from rat cardiac muscle on the basis of a different affinity for DEAE-cellulose and omega-aminobutyl-agarose. One of these fractions was able to transfer glucosyl residues from UDP-glucose not only to glycogen (GS-1 activity) but also to an endogenous acceptor. The latter reaction (GS-2 activity) occurred in the absence of added glycogen, and its reaction product was insoluble in trichloroacetic acid. This compound was degraded by amylolytic enzymes, thus showing that the product synthesized on the endogenous acceptor was an alpha 1,4-glucan. After incubation with alpha-amylase-free proteolytic enzyme, the compound was rendered trichloroacetic acid-soluble. Polyacrylamide gel electrophoresis, under both native and denaturing conditions, showed that GS-2 reaction products moved electrophoretically associated to protein. Our results give further evidence for the association between an alpha 1,4-glucan and protein, which we postulate is related to the initiation of glycogen biosynthesis.
根据对二乙氨基乙基纤维素（DEAE - 纤维素）和ω-氨基丁基琼脂糖的不同亲和力，从大鼠心肌中分离出两种糖原合酶组分。其中一种组分不仅能够将尿苷二磷酸葡萄糖（UDP - 葡萄糖）中的葡萄糖基残基转移到糖原上（GS - 1活性），还能转移到内源性受体上。后一种反应（GS - 2活性）在没有添加糖原的情况下发生，其反应产物不溶于三氯乙酸。该化合物可被淀粉酶降解，因此表明在内源性受体上合成的产物是α-1,4-葡聚糖。在用不含α-淀粉酶的蛋白水解酶孵育后，该化合物变为可溶于三氯乙酸。在天然和变性条件下的聚丙烯酰胺凝胶电泳表明，GS - 2反应产物在电泳时与蛋白质相关联。我们的结果进一步证明了α-1,4-葡聚糖与蛋白质之间的关联，我们推测这与糖原生物合成的起始有关。
