Weber A L, Orgel L E
J Mol Evol. 1979 Oct;13(3):193-202. doi: 10.1007/BF01739479.
The condensation products obtained from 0.01M S-glycyl-N-acetyl-cysteamine at different pH's were investigated. The highest yields of diketopiperazine (approx. 50%) were observed in phosphate buffers between pH 7.5 and 8.5. The highest yields of diglycine (46%), triglycine (10%) and tetraglycine (2%) were observed in carbonate buffers at pH 9.5. At pH 8.0, over 90% of the glycyl residues of 0.15M S-glycyl-N-acetylcysteamine were incorporated into condensation products, mainly DKP (60--70%). The yields of products from the condensation of S-glycyl-ethanethiol under similar conditions closely resembled those obtained with S-glycyl-N-acetylcysteamine.
研究了在不同pH值下由0.01M S-甘氨酰-N-乙酰半胱胺得到的缩合产物。在pH 7.5至8.5的磷酸盐缓冲液中观察到二酮哌嗪的最高产率（约50%）。在pH 9.5的碳酸盐缓冲液中观察到二甘氨酸（46%）、三甘氨酸（10%）和四甘氨酸（2%）的最高产率。在pH 8.0时，0.15M S-甘氨酰-N-乙酰半胱胺中超过90%的甘氨酰残基被并入缩合产物中，主要是二酮哌嗪（60 - 70%）。在类似条件下S-甘氨酰-乙硫醇缩合产物的产率与用S-甘氨酰-N-乙酰半胱胺得到的产率非常相似。
