Chapman G E, Rogers K M, Brittain T, Bradshaw R A, Bates O J, Turner C, Cary P D, Crane-Robinson C
J Biol Chem. 1981 Mar 10;256(5):2395-401.
Extracts of frozen human pituitary glands contain, in addition to normal growth hormone (hGH (Mr = 22,005), a variant of lower molecular weight (approximately 20,000) (Singh, R. N. P., Seavey, B. K. and Lewis, U. J. (1974) Endocrinol. Res. Commun. 1, 449-464). This material, designated 20K hGH, occurs in various forms with the majority present as a heterologous dimer of Mr = 20,000 hGH and hGH. The purification scheme for obtaining the variant from these fractions is described. Analysis of Mr = 20,000 hGH in the sequenator has confirmed that residues 32-46 of hGH are absent in Mr = 20,000 hGH. The structures of hGH and Mr = 20,000 hGH have been compared by 1H nuclear magnetic resonance spectroscopy, circular dichroism, spectrophotometric titration, and nitration of the tyrosine residues by tetranitromethane. The results indicate that the folding of the polypeptide chain of the two proteins is similar but not identical.
冷冻人垂体提取物中，除了正常生长激素（hGH，分子量为22,005）外，还含有一种低分子量变体（约20,000）（辛格，R.N.P.，西维，B.K.和刘易斯，U.J.（1974年）《内分泌研究通讯》1，449 - 464）。这种物质被命名为20K hGH，以多种形式存在，大多数以分子量为20,000的hGH与hGH的异源二聚体形式存在。文中描述了从这些组分中获得该变体的纯化方案。在序列分析仪中对分子量为20,000的hGH进行分析，证实了分子量为20,000的hGH中不存在hGH的32 - 46位残基。通过1H核磁共振光谱、圆二色性、分光光度滴定以及用四硝基甲烷对酪氨酸残基进行硝化反应，对hGH和分子量为20,000的hGH的结构进行了比较。结果表明，这两种蛋白质的多肽链折叠相似但并不相同。
