嗜盐片球菌的柠檬酸盐代谢。
Citrate Metabolism by Pediococcus halophilus.
机构信息
Soy Sauce Research Laboratories, Kikkoman Corporation, Noda-shi, Chiba-ken 278, Japan.
出版信息
Appl Environ Microbiol. 1987 Jun;53(6):1257-62. doi: 10.1128/aem.53.6.1257-1262.1987.
Several strains of non-citrate-metabolizing Pediococcus halophilus have previously been isolated from soy sauce mash or moromi. The factors controlling the metabolism of citrate in soy pediococci were studied. All the soy pediococcal strains tested which failed to decompose citrate did not possess citrate lyase [citrate (pro-3S)-lyase; EC 4.1.3.6] activity. In P. halophilus, citrate lyase was an inducible enzyme, and the optimum pH for activity was 7.0. The metabolism of citrate in P. halophilus was different from that observed in lactic streptococci. The main products from citrate were acetate and formate, and this bacterium produced no acetoin or diacetyl. Formate production from citrate was greatly reduced in the presence of glucose. P. halophilus 7117 (Cit) was proved to contain citrate lyase, pyruvate formate-lyase (EC 2.3.1.54) phosphotransacetylase (phosphate acetyltransferase; EC 2.3.1.8), and acetate kinase (EC 2.7.2.1), i.e., all the enzymes necessary to convert citrate to acetate and formate.
先前已从酱油醪或麴中分离到几种非柠檬酸盐代谢的嗜乳酸片球菌菌株。本研究了控制酱油片球菌中柠檬酸盐代谢的因素。所有测试的不能分解柠檬酸盐的酱油片球菌菌株均不具有柠檬酸裂合酶[柠檬酸（顺式-3S）-裂合酶；EC 4.1.3.6]活性。在嗜乳酸片球菌中，柠檬酸裂合酶是一种诱导酶，其最适 pH 值为 7.0。嗜乳酸片球菌的柠檬酸盐代谢与乳链球菌的观察结果不同。柠檬酸的主要产物为乙酸盐和甲酸盐，该细菌不产生乙酰基丙二酸盐或双乙酰基。在葡萄糖存在下，柠檬酸生成甲酸盐的量大大减少。证明嗜乳酸片球菌 7117（Cit）含有柠檬酸裂合酶、丙酮酸甲酸-裂合酶（EC 2.3.1.54）磷酸转乙酰酶（磷酸乙酰转移酶；EC 2.3.1.8）和乙酸激酶（EC 2.7.2.1），即，将柠檬酸转化为乙酸盐和甲酸盐所需的所有酶。
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