Sibirnyĭ A A, Shavlovskiĭ G M, Ksheminskaia G P, Orlovskaia A G
Biokhimiia. 1977 Oct;42(10):1841-51.
In contrast to cells and protoplasts of the wild strain intact cells and protoplasts of riboflavin (RF)-deficient mutants of Pichia guilliermondii yeast possessing multiple sensitivity to antibiotics and antimetabolites were found capable to accomplish active transport of RF. The accumulation of RF against concentration gradient was energized by endogenous energy sources and was strongly depressed by uncouplers of oxidative phosphorylation and by inhibitors of respiration. RF transport was also blocked by the agents which destroy the permeability barrier and by sucrose. Cyclohemide did not inhibit the transport of vitamin B2. Uptake of RF depends on temperature and pH of the incubation mixture. RF permease possessed rather stringent substrate specificity and did not catalyze transport of FMN and FAD. RF uptake in two strains tested, MS1-3 and MS1, followed saturation kinetics (Km = 0.17 mM and 2.0 mM, respectively) and was not connected with RF auxotrophy. The ability for exogenous RF uptake was controlled by recessive allele. Restoration of normal resistance to antibiotics and antimetabolites was accompanied by a decrease in the permease affinity for substrate.
与野生菌株的细胞和原生质体相比，发现季也蒙毕赤酵母核黄素（RF）缺陷型突变体的完整细胞和原生质体对抗生素和抗代谢物具有多重敏感性，能够完成RF的主动转运。RF逆浓度梯度的积累由内源性能量来源供能，并被氧化磷酸化解偶联剂和呼吸抑制剂强烈抑制。RF转运也被破坏通透性屏障的试剂和蔗糖阻断。放线菌酮不抑制维生素B2的转运。RF的摄取取决于孵育混合物的温度和pH值。RF通透酶具有相当严格的底物特异性，不催化FMN和FAD的转运。在测试的两个菌株MS1-3和MS1中，RF摄取遵循饱和动力学（Km分别为0.17 mM和2.0 mM），且与RF营养缺陷无关。摄取外源RF的能力由隐性等位基因控制。对抗生素和抗代谢物正常抗性的恢复伴随着通透酶对底物亲和力的降低。
