Gentile F, Palumbo G
Centro di Endocrinologia e Oncologia Sperimentale del C. N. R., University of Naples Federico II, Italy.
Biochem Biophys Res Commun. 1993 Nov 15;196(3):1120-6. doi: 10.1006/bbrc.1993.2367.
Upon incubation of bovine thyroglobulin with trypsin at high enzyme/substrate ratio, some fragments with apparent masses between 18 and 31 kDa resisted prolonged digestion. Their NH2-terminal sequences were determined. All fragments overlapped with some of the Cys-rich repeats that compose a large part of thyroglobulin and are predicted to have a rigid structure. Among the inserts that interrupt the cysteine-rich repeats, for which several data indicate a location at the surface of thyroglobulin, the insert of repeat 1.7 was unique because of its resistance to proteolysis. This insert, although exposed at the surface of the protein, may be hidden in a region of contact between thyroglobulin monomers.
在高酶/底物比例下用胰蛋白酶孵育牛甲状腺球蛋白时，一些表观质量在18至31 kDa之间的片段能抵抗长时间消化。测定了它们的氨基末端序列。所有片段都与构成甲状腺球蛋白大部分的一些富含半胱氨酸的重复序列重叠，预计这些重复序列具有刚性结构。在中断富含半胱氨酸重复序列的插入序列中，有几个数据表明其位于甲状腺球蛋白表面，重复序列1.7的插入序列因其对蛋白水解的抗性而独特。这个插入序列虽然暴露在蛋白质表面，但可能隐藏在甲状腺球蛋白单体之间的接触区域。
