在Paracoccus denitrificans中发生乳酸氧化
Geumsoo Kim1, Raul Covian2, Lanelle Edwards2
1Laboratory of Biochemistry, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
Archives of biochemistry and biophysics
|April 17, 2024
概括
帕拉科克斯 (Paracoccus denitrificans) 使用两种新型乳酸脱水酶,D-iLDH和L-iLDH代谢乳酸,这些新型乳酸脱水酶不需要NAD+. 这为乳酸盐提供了直接进入的途径.
科学领域:
- 微生物学 微生物学
- 生物化学 生化学
- 细胞呼吸 细胞呼吸
背景情况:
- 由于其类似的电子运输链,Paracoccus denitrificans作为哺乳动物线粒体的模型.
- 之前的研究重点是用葡萄糖或酸盐呼吸,并指出无法解释的乳酸盐积累.
- 这种细菌缺乏典型的NAD+依赖的乳酸脱酶,促使对乳酸代谢进行调查.
研究的目的:
- 为了阐明Paracoccus denitrificans中乳酸氧化的机制.
- 为了确定该细菌中负责乳酸代谢的酶.
主要方法:
- 使用d-乳酸盐和l-乳酸盐的生长研究.
- 蛋白质组,代谢组和生物化学分析.
- 克隆,生产和表征D-乳酸盐偏好酶 (D-iLDH).
主要成果:
- 帕拉科库斯 (Paracoccus denitrificans) 在d-乳酸盐和l-乳酸盐上都能有效生长,支持高呼吸率.
- 两个非NAD+依赖的乳酸脱酶 (D-iLDH和L-iLDH) 调节乳酸代谢.
- 具有特征的D-iLDH对d-乳酸盐具有很高的亲和力,利用作为电子受体,并将乳酸盐转化为pyruvate.
结论:
- 在P.denitrificans中,乳酸代谢主要由新的,非NAD+依赖的乳酸脱酶介导.
- D-iLDH为乳酸盐衍生的还原剂提供了直接通往电子传输链的途径.
- 这种机制解释了当使用乳酸盐作为基质时细菌的高呼吸能力.
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