Ohshima H, O'Neill I K, Friesen M, Pignatelli B, Bartsch H
IARC Sci Publ. 1984(57):77-85.
A new type of sulfur-containing N-nitrosamino acid, N-nitrosothiazolidine 4-carboxylic acid (NTCA) and N-nitroso 2-methylthiazolidine 4-carboxylic acid (NMTCA), was isolated and identified in the urine of human subjects. Identification was based on identical chromatographic and mass spectral data for the purified urine sample and the synthesized authentic compounds. The amounts of NTCA and NMTCA excreted in 24-h urines of 15 volunteers varied from 0.9 to 35.9 micrograms/day and from 0.4 to 19.8 micrograms/day, respectively. These amounts were 2.4 and 1.6 times greater than that of N-nitrosoproline (NPRO) detected in the same urine samples. Thiazolidine 4-carboxylic acid and its 2-methyl derivative were found to be nitrosated in vitro about 250-500 and 60-300 times more rapidly than proline, respectively. In addition, NTCA and NMTCA were also readily formed by reaction of a mixture of nitrite and L-cysteine, with formaldehyde and acetaldehyde, respectively. Although their origin in human urine is unknown, preliminary results in one human volunteer have shown that some of these compounds are formed endogenously. Thus, measurement of these new sulfur-containing N-nitrosamino acids in the urine may (i) provide another index for endogenous nitrosation reactions in the human body and (ii) allow monitoring of exposure of humans to precursors such as aldehydes and nitrate/nitrite.
一种新型的含硫N-亚硝基氨基酸，N-亚硝基噻唑烷-4-羧酸（NTCA）和N-亚硝基-2-甲基噻唑烷-4-羧酸（NMTCA），已在人体尿液中被分离和鉴定。鉴定是基于纯化尿液样本与合成的标准化合物具有相同的色谱和质谱数据。15名志愿者24小时尿液中排出的NTCA和NMTCA量分别在0.9至35.9微克/天和0.4至19.8微克/天之间。这些量分别比在相同尿液样本中检测到的N-亚硝基脯氨酸（NPRO）高2.4倍和1.6倍。发现噻唑烷-4-羧酸及其2-甲基衍生物在体外被亚硝化的速度分别比脯氨酸快约250 - 500倍和60 - 300倍。此外，NTCA和NMTCA也分别通过亚硝酸盐与L-半胱氨酸的混合物与甲醛和乙醛反应而容易形成。虽然它们在人尿中的来源尚不清楚，但在一名人类志愿者中的初步结果表明，其中一些化合物是内源性形成的。因此，测量尿液中这些新的含硫N-亚硝基氨基酸可能（i）为人体中的内源性亚硝化反应提供另一个指标，并且（ii）允许监测人体对醛类和硝酸盐/亚硝酸盐等前体的暴露情况。
