Weber A L
J Mol Evol. 1983;19(3-4):237-43. doi: 10.1007/BF02099971.
The formation of lactate from glyceraldehyde is catalyzed by the thiol, N-acetylcysteine, at ambient temperature in aqueous sodium phosphate (pH 7.0). The rate of lactate formation is more rapid at higher concentrations of sodium phosphate and is essentially the same in the presence and absence of oxygen. The formation of lactate is efficient, but proceeds slowly with an 8.8% yield of lactate after 16 days from 10 mM glyceraldehyde in the presence of 12.5 mM N-acetylcysteine and 500 mM sodium phosphate (pH 7.0). The formation of glycerate from glyceraldehyde, that occurs in the presence of oxygen and to a small extent when oxygen has been removed, is also catalyzed by the thiol, N-acetylcysteine, under the same conditions. The dramatic increase in the rate of glycerate formation that is brought about by the thiol, N-acetylcysteine, is accompanied by an equally dramatic decrease in the rates of production of glycolate and formate. Presumably, the thiol-dependent formation of lactate and glycerate occurs via their respective thioesters. The significance of these reactions to molecular evolution is discussed.
在磷酸钠水溶液（pH 7.0）中，在环境温度下，甘油醛形成乳酸是由硫醇N - 乙酰半胱氨酸催化的。在较高浓度的磷酸钠存在下，乳酸形成的速率更快，并且在有氧和无氧条件下基本相同。乳酸的形成是有效的，但在12.5 mM N - 乙酰半胱氨酸和500 mM磷酸钠（pH 7.0）存在下，从10 mM甘油醛开始，16天后乳酸的产率为8.8%，反应进行得较慢。在相同条件下，硫醇N - 乙酰半胱氨酸也催化甘油醛在有氧存在时以及在去除氧气后少量情况下形成甘油酸。硫醇N - 乙酰半胱氨酸引起的甘油酸形成速率的显著增加伴随着乙醇酸和甲酸生成速率同样显著的降低。推测，硫醇依赖性的乳酸和甘油酸形成是通过它们各自的硫酯进行的。讨论了这些反应对分子进化的意义。
