Kamitakahara J R, Polglase W J
Biochem J. 1970 Dec;120(4):771-5. doi: 10.1042/bj1200771.
The yield of cell protein was one-third less for streptomycin-dependent Escherichia coli B than for the wild-type parent strain when both were grown aerobically on a medium with limiting glucose, but anaerobically the yield of protein was similar for both strains. The transient pigment absorbing at 503nm that is known to be present in E. coli and other organisms was not detectable in streptomycin-dependent mutants nor in a non-dependent (energy-deficient) revertant. When wild-type E. coli B was grown on limiting glucose-salts medium containing 2,4 dinitrophenol, the yield of cell protein was decreased and formation of the 503nm pigment was inhibited. Fumarase, aconitase and glucose 6-phosphate dehydrogenase were de-repressed in E. coli B cells grown with excess of glucose in a medium containing 2,4-dinitrophenol. In air-oxidized, wild-type E. coli B cells, the 503nm pigment appeared before reduced cytochromes when gluconate was the substrate but failed to appear when succinate was the substrate. The results provide evidence for a role of the 503nm pigment in aerobic energy metabolism, possibly as an electron acceptor from NADPH.
当链霉素依赖型大肠杆菌B和野生型亲本菌株在含有限制性葡萄糖的培养基上需氧生长时，细胞蛋白产量比野生型亲本菌株少三分之一，但在厌氧条件下，两种菌株的蛋白产量相似。已知存在于大肠杆菌和其他生物体中的在503nm处吸收的瞬时色素，在链霉素依赖型突变体和非依赖型（能量缺陷型）回复突变体中均未检测到。当野生型大肠杆菌B在含2,4 -二硝基苯酚的限制性葡萄糖盐培养基上生长时，细胞蛋白产量降低，503nm色素的形成受到抑制。在含有2,4 -二硝基苯酚且葡萄糖过量的培养基中生长的大肠杆菌B细胞中，延胡索酸酶、乌头酸酶和葡萄糖6 -磷酸脱氢酶被去阻遏。在空气氧化的野生型大肠杆菌B细胞中，当葡萄糖酸盐作为底物时，503nm色素在还原型细胞色素之前出现，但当琥珀酸盐作为底物时则未出现。这些结果为503nm色素在有氧能量代谢中的作用提供了证据，可能作为来自NADPH的电子受体。
