Castro I M, Loureiro-Dias M C
Laboratory of Microbiology, Gulbenkian Institute of Science, Oeiras, Portugal.
J Gen Microbiol. 1991 Jul;137(7):1497-502. doi: 10.1099/00221287-137-7-1497.
Glycerol was transported in the fungus Fusarium oxysporum var. lini by a facilitated diffusion transport system with a half-saturation constant, Ks, of 0.5 mM and a maximum velocity, Vmax, of 0.9 mmol (g dry wt)-1 h-1 at pH 5 and 25 degrees C. 1,2-Propanediol was a competitive inhibitor of glycerol transport, but the cells did not actively accumulate 1,2-propanediol. The transport system was partially constitutive. In cells grown in the presence of glucose, glycerol was not transported, indicating that the synthesis of the system was under glucose repression. Glycerol kinase and NADP(+)-dependent glycerol dehydrogenase activities were present under all physiological conditions tested. A flavin-dependent glycerol phosphate dehydrogenase was induced only when glycerol was the sole energy source in the medium. This enzyme, together with the transport system, constitute the regulated steps in the glycerol metabolic pathway.
在尖孢镰刀菌亚麻变种中，甘油通过一种易化扩散转运系统进行转运，在pH 5和25℃条件下，其半饱和常数Ks为0.5 mM，最大速度Vmax为0.9 mmol（干重g）-1 h-1。1,2 - 丙二醇是甘油转运的竞争性抑制剂，但细胞不会主动积累1,2 - 丙二醇。该转运系统部分组成型表达。在葡萄糖存在下生长的细胞中，甘油不被转运，这表明该系统的合成受葡萄糖阻遏。在所测试的所有生理条件下均存在甘油激酶和依赖NADP(+)的甘油脱氢酶活性。仅当甘油是培养基中的唯一能量来源时，才会诱导出黄素依赖性甘油磷酸脱氢酶。这种酶与转运系统一起，构成了甘油代谢途径中的调控步骤。
