萌发中食松幼苗淀粉合酶同工酶与淀粉成分的关系

利用14C－ADPG标定法测定可溶性及与淀粉粒结合的淀粉合酶活性，采用过氯酸抽提、DMSO玻璃纤维纸层析、硫酸水解法定量测定各类淀粉成分，探讨了食松（PinusedulisEngelm）幼苗生长过程中淀粉合酶与淀粉成分间的关系。结果表明，在胚根出现以后，淀粉含量迅速增加，伴随着淀粉颗粒数目和质量的增加，两类淀粉合酶活性的增加以及淀粉合酶免疫印迹图谱的变化。支链淀粉是食松淀粉的主要成分，占总淀粉的84％。可溶性淀粉合酶峰值比淀粉粒结合的淀粉合酶活性峰值高1．3倍，与支链淀粉和直链淀粉的比例相对应。结果支持食松可溶性淀粉合酶是负责支链淀粉合成的主要酶的假说，同时表明淀粉粒结合的淀粉合酶在支链淀粉的合成中也有作用。

Relationship Between Isozymes of Starch Synthases and Starch Composition in Germinating Pinyon Seedlings

The relation between starch synthases and starch composition in the germinating pinyon (Pinus edulis Engelm) seedlings was studied. Using the method of 14C-glucose transferred for 14C-ADPG in the assay of starch synthases activity. Starch was extracted with 32% HClO4, separated on glass fiber with DMSO, and assayed with the sulfuric acid-phenol method. After the emergence of radicle, starch content increased rapidly arcompanied with the incnae of starch grains in number and size, the increase of both solube and granulebound starch synthase activity and the change of the patterm of Western-blot. Amylopectin was the major composition in pinyon starch, accounted for 84% of the total starch. The activity of soluble starch synthase was 1. 3 times higher that that of the granule-bound starch synthase, corresponding to the ratio of amylopectin to amylose. This result supports the conventional theory that soluble starch synthase is the major enzyme responsive for the synthesis of amylopectin, and the supports that granule-bound starch synthase is functional in the synthesis of amylopectin.