Gupta V J, Wilcken D E
Eur J Clin Invest. 1978 Aug;8(4):205-7. doi: 10.1111/j.1365-2362.1978.tb00853.x.
Cysteine-homocysteine mixed disulphide, formed in the degradation of methionine, is detected routinely in the plasma of fasting patients homozygous for homocystinuria and in some obligate heteroxygotes. It has not hitherto been identified in the plasma of normal fasting man. Using a highly cross-linked resin with lithium citrate buffers on a JEOL. Amino Acid Analyser, we have detected the mixed disulphide in every one of the plasma samples from twenty normal fasting subjects. The mean concentration was 3.25 mumol/l (SD 0.85, N = 20), with a range of from 1.68 to 4.85 mumol/l. The other neutral and acidic amino acids were within the accepted normal range. The study shows that circulating homocysteine is normally not immediately transformed to cystathionine or remethylated to methionine; some combines with cysteine to form measurable amounts of mixed disulphide. Since homocysteine may produce endothelial damage, the present findings could be relevant to an understanding of the pathogenesis of vascular disease.
在蛋氨酸降解过程中形成的半胱氨酸 - 同型半胱氨酸混合二硫化物，在同型胱氨酸尿症纯合子的空腹患者血浆以及一些 obligate 杂合子中可常规检测到。迄今为止，在正常空腹男性血浆中尚未鉴定出该物质。我们使用一种高度交联的树脂，搭配柠檬酸锂缓冲液，在 JEOL 氨基酸分析仪上，从 20 名正常空腹受试者的每份血浆样本中均检测到了这种混合二硫化物。平均浓度为 3.25 μmol/L（标准差 0.85，N = 20），范围在 1.68 至 4.85 μmol/L 之间。其他中性和酸性氨基酸均在公认的正常范围内。该研究表明，循环中的同型半胱氨酸通常不会立即转化为胱硫醚或重新甲基化为蛋氨酸；部分会与半胱氨酸结合形成可测量量的混合二硫化物。由于同型半胱氨酸可能会造成内皮损伤，目前的研究结果可能与理解血管疾病的发病机制相关。
