Miranda M, Ramos A, Veiga-da-Cunha M, Loureiro-Dias M C, Santos H
Instituto de Tecnologia Química e Biológica/Instituto de Biologia Experimental e Tecnológica, Universidade Nova de Lisboa, Oeiras, Portugal.
J Bacteriol. 1997 Sep;179(17):5347-54. doi: 10.1128/jb.179.17.5347-5354.1997.
The sugar-induced inhibition of malolactic fermentation in cell suspensions of Leuconostoc oenos, recently reclassified as Oenococcus oeni (L. M. T. Dicks, F. Dellaglio, and M. D. Collins, Int. J. Syst. Bacteriol. 45:395-397, 1995) was investigated by in vivo and in vitro nuclear magnetic resonance (NMR) spectroscopy and manometric techniques. At 2 mM, glucose inhibited malolactic fermentation by 50%, and at 5 mM or higher it caused a maximum inhibitory effect of ca. 70%. Galactose, trehalose, maltose, and mannose caused inhibitory effects similar to that observed with glucose, but ribose and 2-deoxyglucose did not affect the rate of malolactic activity. The addition of fructose or citrate completely relieved the glucose-induced inhibition. Glucose was not catabolized by permeabilized cells, and inhibition of malolactic fermentation was not observed under these conditions. 31P NMR analysis of perchloric acid extracts of cells obtained during glucose-malate cometabolism showed high intracellular concentrations of glucose-6-phosphate, 6-phosphogluconate, and glycerol-3-phosphate. Glucose-6-phosphate, 6-phosphogluconate, and NAD(P)H inhibited the malolactic activity in permeabilized cells or cell extracts, whereas NADP+ had no inhibitory effect. The purified malolactic enzyme was strongly inhibited by NADH, whereas all the other above-mentioned metabolites exerted no inhibitory effect, showing that NADH was responsible for the inhibition of malolactic activity in vivo. The concentration of NADH required to inhibit the activity of the malolactic enzyme by 50% was ca. 25 microM. The data provide a coherent biochemical basis to understand the glucose-induced inhibition of malolactic fermentation in L. oenos.
利用体内和体外核磁共振（NMR）光谱以及测压技术，研究了糖对酒酒球菌（最近重新分类为嗜酒片球菌，L.M.T.迪克斯、F.德拉廖和M.D.柯林斯，《国际系统细菌学杂志》45:395 - 397，1995）细胞悬液中苹果酸 - 乳酸发酵的抑制作用。在2 mM时，葡萄糖对苹果酸 - 乳酸发酵的抑制率为50%，在5 mM或更高浓度时，其最大抑制效果约为70%。半乳糖、海藻糖、麦芽糖和甘露糖产生的抑制作用与葡萄糖相似，但核糖和2 - 脱氧葡萄糖不影响苹果酸 - 乳酸发酵速率。添加果糖或柠檬酸盐可完全解除葡萄糖诱导的抑制作用。葡萄糖不能被透性化细胞分解代谢，在这些条件下未观察到对苹果酸 - 乳酸发酵的抑制作用。对葡萄糖 - 苹果酸共代谢过程中获得的细胞高氯酸提取物进行的31P NMR分析表明，细胞内葡萄糖 - 6 - 磷酸、6 - 磷酸葡萄糖酸和甘油 - 3 - 磷酸浓度较高。葡萄糖 - 6 - 磷酸、6 - 磷酸葡萄糖酸和NAD(P)H抑制透性化细胞或细胞提取物中的苹果酸 - 乳酸活性，而NADP + 没有抑制作用。纯化的苹果酸 - 乳酸酶受到NADH的强烈抑制，而上述所有其他代谢物均无抑制作用，表明NADH是体内苹果酸 - 乳酸活性抑制的原因。抑制苹果酸 - 乳酸酶活性50%所需的NADH浓度约为25 microM。这些数据为理解葡萄糖诱导的酒酒球菌中苹果酸 - 乳酸发酵抑制提供了一个连贯的生化基础。
