肠道蔗糖酶 - 异麦芽糖酶和葡糖淀粉酶的体外翻译
In vitro translation of intestinal sucrase-isomaltase and glucoamylase.
作者信息
Alpers D H, Helms D, Seetharam S, May V L, Strauss A W
出版信息
Biochem Biophys Res Commun. 1986 Jan 14;134(1):37-43. doi: 10.1016/0006-291x(86)90523-1.
It is has been proposed that both sucrase-isomaltase and glucoamylase are initially synthesized as large single-chain precursors which are then processed to heterodimers. We have tested this hypothesis by in vitro translation of their mRNAs. The primary translation product of sucrase-isomaltase mRNA was a single polypeptide of Mr = 190,000. Similar experiments using antiserum against glucoamylase revealed a single polypeptide of Mr = 145,000. These results are consistent with the single chain precursor hypothesis for sucrase-isomaltase. However, the glucoamylase product (145 kDa) is too small to be processed to a heterodimer of Mr = 230,000. Moreover, the mature subunits (Mr = 135,000 and 125,000) probably are derived from the 145 kDa precursor by proteolytic trimming and must include and share most of the precursor protein.
有人提出，蔗糖酶 - 异麦芽糖酶和葡糖淀粉酶最初都是作为大的单链前体合成的，然后加工成异二聚体。我们通过体外翻译它们的mRNA来检验这一假设。蔗糖酶 - 异麦芽糖酶mRNA的初级翻译产物是一条分子量为190,000的单多肽链。使用抗葡糖淀粉酶抗血清进行的类似实验显示出一条分子量为145,000的单多肽链。这些结果与蔗糖酶 - 异麦芽糖酶的单链前体假说是一致的。然而，葡糖淀粉酶产物（145 kDa）太小，无法加工成分子量为230,000的异二聚体。此外，成熟亚基（分子量为135,000和125,000）可能是通过蛋白水解修剪从145 kDa前体衍生而来的，并且必须包含并共享大部分前体蛋白。
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