Broome M C, Thomas M P, Hillier A J, Jago G R
Aust J Biol Sci. 1980 Mar;33(1):15-25.
Pyruvate dehydrogenase activity was detected in whole cells but not in cell-free extracts of Streptococcus lactis. However, the three component enzymes (pyruvate decarboxylase, lipoate acetyltransferase and lipoyl dehydrogenase) of the pyruvate dehydrogenase complex were identified in the cell-free extracts. Whole cells of the three species of group N streptococci formed acetoin and diacetyl only after the pathway forming acetate had become saturated. S. lactis subsp. diacetylactis DRC2 formed more acetoin and diacetyl and less acetate from pyruvate than did S. lactis C10. Strains C10 and DRC2 were able to form acetoin via alpha-acetolactate or diacetyl and to convert acetoin to butane-2,3-diol. S. cremoris HP was able to form acetoin only via alpha-acetolactate and could not convert acetoin to butane-2,3-diol.
在乳酸链球菌的全细胞中检测到丙酮酸脱氢酶活性，但在无细胞提取物中未检测到。然而，在无细胞提取物中鉴定出了丙酮酸脱氢酶复合体的三种组成酶（丙酮酸脱羧酶、硫辛酸乙酰转移酶和硫辛酰胺脱氢酶）。N群链球菌的三个菌种的全细胞仅在形成乙酸盐的途径饱和后才形成乙偶姻和双乙酰。乳酸乳球菌亚种双乙酰乳杆菌DRC2从丙酮酸形成的乙偶姻和双乙酰比乳酸乳球菌C10更多，而乙酸盐更少。C10和DRC2菌株能够通过α-乙酰乳酸或双乙酰形成乙偶姻，并将乙偶姻转化为2,3-丁二醇。嗜热链球菌HP仅能通过α-乙酰乳酸形成乙偶姻，且不能将乙偶姻转化为2,3-丁二醇。
