Hirose K, Chumnantana R, Nakashima T, Ashiuchi M, Yagi T
Department of Bioresources Science, Faculty of Agriculture, Kochi University, Nankoku Kochi, Japan.
Biosci Biotechnol Biochem. 2000 Dec;64(12):2675-9. doi: 10.1271/bbb.64.2675.
Pyridoxine-charged Schizosaccharomyces pombe released pyridoxine rapidly at 30 degrees C: very low amounts of three other B6 vitamers were also released. The rate of efflux was temperature-dependent. The initial rate of efflux was dependent on the concentration of pyridoxine in the cells: the rate was almost zero at lower than 0.02 mM and became saturated at higher than 0.2 mM. Na+, sodium azide, and dinitrophenol increased the rate in both the presence and absence of D-glucose. Mg++, thiamine, and menadione inhibited the efflux. The intracellular concentration of ATP did not significantly affect the efflux rate. The system may be dependent on a membrane potential of the yeast cells. It was found that the fission yeast cells have a gate or carrier system for efflux of pyridoxine, which was distinct from that in Saccharomyces cerevisiae.
用吡哆醇装载的粟酒裂殖酵母在30℃时能迅速释放吡哆醇：同时也释放出极少量的其他三种B6维生素。流出速率取决于温度。流出的初始速率取决于细胞中吡哆醇的浓度：低于0.02 mM时速率几乎为零，高于0.2 mM时达到饱和。在有和没有D-葡萄糖的情况下，Na⁺、叠氮化钠和二硝基苯酚都会增加流出速率。Mg²⁺、硫胺素和甲萘醌会抑制流出。细胞内ATP的浓度对流出速率没有显著影响。该系统可能依赖于酵母细胞的膜电位。研究发现，裂殖酵母细胞具有一个用于吡哆醇流出的门控或载体系统，这与酿酒酵母中的不同。
