Tsukamoto S, Kanegae T, Nagoya T, Shimamura M, Mieda Y, Nomura M, Hojo K, Okubo H
Department of Legal Medicine, Nihon University School of Medicine.
Arukoru Kenkyuto Yakubutsu Ison. 1990 Oct;25(5):429-40.
Condensation reactions between some SH-amino acids (L-and D-cysteine 1%) and acetaldehyde (50 microM) were studied in vitro experiment. In the aqueous solution, free acetaldehyde was reduced to 41.3% by L-cysteine and to 36.4% by D-cysteine. In the reaction with human blood medium, after the medium was deproteinized with perchloric acid reagent, acetaldehyde was reduced to 47.0% by L-cysteine and to 43.8% by D-cysteine. D-Cysteine appears to have great stability of reacting acetaldehyde. In vitro experiment reactability for D-cysteine exhibited 3-8% higher than that for L-cysteine. Next, effects of some amino acids on alcohol metabolism were studied in male ICR mice. The animals were given ethanol through a gastric catheter at a dose of 2 g/kg and they were intraperitoneally injected L-cysteine (300 mg/kg), D-cysteine (300 mg/kg), L-alanine (300 mg/kg) and control (saline), respectively in the period of one hour before the injection of ethanol. Blood and tissues samples were analyzed for ethanol, acetaldehyde, acetate and acetone during alcohol intoxication in mice by head space gas chromatography. In the groups administered D-cysteine and L-cysteine, the mice showed a definitely faster oxidation and disappearance of ethanol. Especially in the D-cysteine group, ethanol levels in blood, liver and brain remained lower than that in the other groups (p less than 0.01). Acetaldehyde levels in blood, liver and brain remained low by L-cysteine. Ethanol metabolites during alcohol oxidation by chemical reactabilities of L- and D-cysteine showed different distribution in the mice, respectively. In the mice received L-alanine, acetate and acetone levels in blood, liver and brain were distinctly reduced (p less than 0.01). L-Alanine is reported to supply an abundance of pyruvic acid that performs the NAD-generating system. NAD produced is introduced to alcohol metabolism and the TCA cycle. It was thus presumed that the L- or/and D-cysteine, and L-alanine was effective in acute alcohol intoxication by heavy drinking.
在体外实验中研究了一些含巯基氨基酸（L-和D-半胱氨酸1%）与乙醛（50微摩尔）之间的缩合反应。在水溶液中，L-半胱氨酸将游离乙醛还原至41.3%，D-半胱氨酸将其还原至36.4%。在与人血培养基的反应中，用高氯酸试剂使培养基脱蛋白后，L-半胱氨酸将乙醛还原至47.0%，D-半胱氨酸将其还原至43.8%。D-半胱氨酸与乙醛反应时似乎具有很高的稳定性。在体外实验中，D-半胱氨酸的反应性比L-半胱氨酸高3 - 8%。接下来，在雄性ICR小鼠中研究了一些氨基酸对酒精代谢的影响。通过胃管给动物注射2克/千克剂量的乙醇，并在注射乙醇前1小时分别腹腔注射L-半胱氨酸（300毫克/千克）、D-半胱氨酸（300毫克/千克）、L-丙氨酸（300毫克/千克）和对照组（生理盐水）。通过顶空气相色谱法分析小鼠酒精中毒期间血液和组织样本中的乙醇、乙醛、乙酸盐和丙酮。在给予D-半胱氨酸和L-半胱氨酸的组中，小鼠显示出乙醇的氧化和消失明显更快。特别是在D-半胱氨酸组中，血液、肝脏和大脑中的乙醇水平低于其他组（p < 0.01）。L-半胱氨酸使血液中的乙醛水平降低。L-和D-半胱氨酸的化学反应性在酒精氧化过程中产生的乙醇代谢产物在小鼠体内分别呈现不同的分布。在接受L-丙氨酸的小鼠中，血液、肝脏和大脑中的乙酸盐和丙酮水平明显降低（p < 0.01）。据报道，L-丙氨酸提供大量的丙酮酸，丙酮酸参与生成NAD的系统。产生的NAD被引入酒精代谢和三羧酸循环。因此推测，L-或/和D-半胱氨酸以及L-丙氨酸对大量饮酒引起的急性酒精中毒有效。
