Paynovich R C, Carpenter F H
Int J Pept Protein Res. 1979 Feb;13(2):113-21. doi: 10.1111/j.1399-3011.1979.tb01858.x.
A modified procedure for the preparation of the S-sulfonates of the A- and B-chains of insulin and their conversion to the sulfhydryl forms by tri-n-butylphosphine is described. Air oxidation of the sulfhydryl forms of the A-chain in dilute solution (0.2 mg/ml) either in the presence or absence of urea at pH 9.0 yields primarily monomeric, intrachain disulfides. Similar treatment of the reduced B-chain yield monomeric, intrachain disulfide in 7 M urea but a large number of oligomeric, interchain disulfides in the absence of urea. Electrolytic reduction of insulin in 7 M urea of pH 8.5, followed by oxidation of the sulfhydryls in dilute solution in 7 M urea at pH 9.0 yields primarily a mixture of the monomeric, intrachain disulfides of the A-chain and of the B-chain which can be separated by chromatography on Sp-Sephadex in acidic urea. The rate of the oxidation of the sulfhydryls of the two separate chains was much slower and less complete than that reported for the two chains crosslinked by the carbonylbismethionyl residue.
本文描述了一种改良方法，用于制备胰岛素A链和B链的S-磺酸盐，并通过三正丁基膦将其转化为巯基形式。在pH 9.0的稀溶液（0.2 mg/ml）中，无论有无尿素存在，A链巯基形式的空气氧化主要产生单体链内二硫键。对还原的B链进行类似处理，在7 M尿素中产生单体链内二硫键，但在无尿素时产生大量寡聚链间二硫键。在pH 8.5的7 M尿素中对胰岛素进行电解还原，然后在pH 9.0的7 M尿素稀溶液中氧化巯基，主要产生A链和B链单体链内二硫键的混合物，可通过在酸性尿素中的Sp-Sephadex柱色谱分离。两条单独链的巯基氧化速率比通过羰基双甲硫氨酸残基交联的两条链的氧化速率慢得多且不完全。
