Feairheller S H, Taylor M M, Bailey D G
Adv Exp Med Biol. 1977;86B:177-86. doi: 10.1007/978-1-4757-9113-6_11.
Cattle hair exposed to solutions of 35S-sulfide ions at pH 12.5, hydrolyzed with acid, and analyzed for amino acids with simultaneous measurement of the radioactivity of the eluate from the analytical column showed 87 percent of the radioactivity incorporated in the hair in three amino acids: cysteic acid, lanthionine, and cystine. This and other evidence presented lend further support to the intermediacy of dehydroalanyl residues formed by a beta-elimination reaction in the conversion of cystinyl residues to lanthionyl residues in proteins. The presence of radioactively labelled cystine in the hydrolyzate indicates that the dehydroalanyl residues are also capable of reforming cystinyl residues under these same conditions through a series of reversible reactions.
将牛毛置于pH值为12.5的35S - 硫化物离子溶液中,用酸水解,然后对氨基酸进行分析,并同时测量分析柱洗脱液的放射性。结果显示,毛发中87%的放射性存在于三种氨基酸中:半胱磺酸、羊毛硫氨酸和胱氨酸。本文所呈现的这一结果及其他证据,进一步支持了在蛋白质中胱氨酰残基转化为羊毛硫氨酰残基的过程中,由β - 消除反应形成的脱氢丙氨酰残基作为中间体的观点。水解产物中存在放射性标记的胱氨酸,这表明在相同条件下,脱氢丙氨酰残基也能够通过一系列可逆反应重新形成胱氨酰残基。