Membrane-bound L- and D-lactate dehydrogenase activities of a newly isolated Pseudomonas stutzeri strain
Membrane-bound L- and D-lactate dehydrogenase activities of a newly isolated Pseudomonas stutzeri strain
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新分离的施氏假单胞菌菌株的膜结合 L- 和 D- 乳酸脱氢酶活性
DOI：
10.1007/s00253-007-1132-4
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发表时间：
2007-11-01
影响因子：
5
通讯作者：
Xu, Ping
中科院分区：
文献类型：
--
作者：
Ma, Cuiqing;Gao, Chao;Xu, Ping
施氏假单胞菌（PseudomonasstutzeriSDM）是从土壤中分离到的一株新菌株，在以DL-乳酸为唯一碳源的培养基中培养时，在细胞膜上检测到两种立体专一的NAD非依赖性乳酸脱氢酶（iLDH）活性。这两种酶的活性都不是组成型的，但它们都可能由乳酸的任一对映体诱导。当L-乳酸和葡萄糖都可利用时，施氏原杆菌SDM更喜欢利用乳酸来生长，并且只有在乳酸耗尽后才观察到葡萄糖的消耗。L-乳酸的米氏常数大于D-乳酸。L-iLDH活性在55 ℃下更稳定，而D-iLDH活性丧失。这两种酶表现出不同的溶解与不同的洗涤剂和不同的氧化速率与不同的电子受体。结合活性染色和之前的蛋白质组学分析，结果表明斯氏原杆菌SDM中存在两种不同的酶，它们在将乳酸转化为丙酮酸方面发挥着重要作用。
Pseudomonas stutzeri SDM was newly isolated from soil, and two stereospecific NAD-independent lactate dehydrogenase (iLDH) activities were detected in membrane of the cells cultured in a medium containing DL-lactate as the sole carbon source. Neither enzyme activities was constitutive, but both of them might be induced by either enantiomer of lactate. P. stutzeri SDM preferred to utilize lactate to growth, when both L-lactate and glucose were available, and the consumption of glucose was observed only after lactate had been exhausted. The Michaelis-Menten constant for L-lactate was higher than that for D-lactate. The L-iLDH activity was more stable at 55 degrees C, while the D-iLDH activity was lost. Both enzymes exhibited different solubilization with different detergents and different oxidation rates with different electron acceptors. Combining activity staining and previous proteomic analysis, the results suggest that there are two separate enzymes in P. stutzeri SDM, which play an important role in converting lactate to pyruvate.