Lees G J
J Dairy Res. 1976 Feb;43(1):63-73. doi: 10.1017/s0022029900015600.
Group N streptococci formed acetaldehyde and ethanol from glucose. As the enzymes aldehyde dehydrogenase, phosphotransacetylase and acetate kinase were present this would enable these organisms to reduce acetyl-CoA to acetaldehyde and convert acetyl-CoA to acetyl phosphate and acetate. A pentose phosphate pathway which converted ribose-5-phosphate to glyceraldehyde-3-phosphate was also present. Acetaldehyde could not be formed via the hexose monophosphate shunt or by direct decarboxylation of pyruvate, as the enzymes phosphoketolase and alpha-carboxylase were absent. Phosphoketolase activity was induced in Streptococcus lactis subsp. diacetylactis after growth on D-xylose. Group N streptococci also contained an NAD-dependent alcohol dehydrogenase which reduced acetaldehyde to ethanol while both NAD- and NADP-dependent alcohol dehydrogenase activities were found in Leuconostoc cremoris.
N 群链球菌可利用葡萄糖生成乙醛和乙醇。由于存在醛脱氢酶、磷酸转乙酰酶和乙酸激酶，这些生物体能够将乙酰辅酶 A 还原为乙醛，并将乙酰辅酶 A 转化为乙酰磷酸和乙酸。还存在一条将核糖 -5- 磷酸转化为甘油醛 -3- 磷酸的戊糖磷酸途径。由于缺乏磷酸酮醇酶和α - 羧化酶，无法通过己糖磷酸支路或丙酮酸的直接脱羧作用形成乙醛。在乳酸乳球菌亚种双乙酰乳酸亚种在 D - 木糖上生长后可诱导产生磷酸酮醇酶活性。N 群链球菌还含有一种依赖 NAD 的醇脱氢酶，可将乙醛还原为乙醇，而在乳明串珠菌中同时发现了依赖 NAD 和依赖 NADP 的醇脱氢酶活性。
