Yamashoji Shiro
Microbial Technology Laboratory, Kaigan-dori 9-50-514, Tarumin-ku, Kobe 655-0036, Japan.
Biochem Biophys Rep. 2016 Mar 21;6:88-93. doi: 10.1016/j.bbrep.2016.03.007. eCollection 2016 Jul.
Menadione promoted the production of active oxygen species (AOS) in both yeast cell suspension and the crude enzymes from the cells, but menadione sodium bisulfite (MSB) had little effect on the production of AOS in the cell suspension. MSB kept the stable increase in the electron transfer from intact yeast cells to anode compared to menadione, but the electron transfer promoted by MSB was inhibited in permeabilized yeast cell suspension. Menadione promoted oxidation of NAD(P)H much faster than MSB in permeabilized yeast cell suspension, suggesting the oxidative stress due to consumption of NAD(P)H. The proliferation of yeast cells was inhibited by menadione under aerobic conditions rather than anaerobic conditions, and the inhibitory effect was reduced by superoxide dismutase and catalase. The effect of MSB on the proliferation was much smaller than that of menadione. The above facts suggest that harmless MSB promotes the electron transfer from plasma membrane of yeast cells to anode. On the other hand, harmful menadione might promote the electron transfer from cytosol and plasma membrane to anode and dissolved oxygen.
甲萘醌可促进酵母细胞悬液和细胞粗酶中活性氧（AOS）的产生，但亚硫酸氢钠甲萘醌（MSB）对细胞悬液中AOS的产生几乎没有影响。与甲萘醌相比，MSB使完整酵母细胞向阳极的电子转移保持稳定增加，但在透化酵母细胞悬液中，MSB促进的电子转移受到抑制。在透化酵母细胞悬液中，甲萘醌比MSB更快地促进NAD（P）H的氧化，这表明由于NAD（P）H的消耗导致氧化应激。在有氧条件下而非厌氧条件下，甲萘醌抑制酵母细胞的增殖，超氧化物歧化酶和过氧化氢酶可降低这种抑制作用。MSB对增殖的影响远小于甲萘醌。上述事实表明，无害的MSB促进酵母细胞质膜向阳极的电子转移。另一方面，有害的甲萘醌可能促进从细胞质和质膜到阳极和溶解氧的电子转移。
