Grochowski Laura L, Xu Huimin, White Robert H
Department of Biochemistry (0308), Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
J Bacteriol. 2006 Apr;188(8):2836-44. doi: 10.1128/JB.188.8.2836-2844.2006.
One of the early steps in the biosynthesis of coenzyme F(420) in Methanocaldococcus jannaschii requires generation of 2-phospho-L-lactate, which is formed by the phosphorylation of L-lactate. Preliminary studies had shown that L-lactate in M. jannaschii is not derived from pyruvate, and thus an alternate pathway(s) for its formation was examined. Here we report that L-lactate is formed by the NAD(+)-dependent oxidation of l-lactaldehyde by the MJ1411 gene product. The lactaldehyde, in turn, was found to be generated either by the NAD(P)H reduction of methylglyoxal or by the aldol cleavage of fuculose-1-phosphate by fuculose-1-phosphate aldolase, the MJ1418 gene product.
詹氏甲烷嗜热菌中辅酶F(420)生物合成的早期步骤之一需要生成2-磷酸-L-乳酸，它由L-乳酸磷酸化形成。初步研究表明，詹氏甲烷嗜热菌中的L-乳酸并非源自丙酮酸，因此研究了其形成的替代途径。在此我们报告，L-乳酸由MJ1411基因产物通过NAD(+)依赖的L-乳醛氧化形成。反过来，发现乳醛要么由甲基乙二醛的NAD(P)H还原产生，要么由MJ1418基因产物果糖-1-磷酸醛缩酶对果糖-1-磷酸的醛醇裂解产生。
