Miller D M, Harun S H
Biochim Biophys Acta. 1978 Dec 19;514(2):320-31. doi: 10.1016/0005-2736(78)90302-4.
The kinetics of the uptake and efflux of 3-O-methyl-glucose in sporidia of Ustilago maydis were measured, both in active cells and in cells whose metabolic activity had been inhibited by azide and iodoacetate. The de-energized transport system proved to be carrier mediated with apparent affinity constants 13 +/- 2 mM outside (Ko) and 18 +/- 2 mM inside (K1). The apparent maximum rate constants for the same system were 0.66 +/- 0.05 mmol/1 cell water per min for uptake (V+) and 0.53 +/- 0.04 mmol/l cell water per min for efflux (V-). For the active system K0 = 0.08 +/- 0.01, K1 greater than 40, V+ = 9.7 +/- 0.5 and V- = 1.1 +/- 0.9 (in equivalent units). These results are discussed in the context of the carrier mechanism as proposed by Regen and Morgan (Regen, D.M. and Morgan, H.E. (1964) Biochim. Biophys. Acta 79, 151--166). The antifungal compound carboxin had no effect on de-energized transport but was shown to decrease both K0 And V+ in the active system. Phloretin and phlorizin were also found to be without effect on de-energized cells but the former enhanced while the latter inhibited active uptake.
测定了玉米黑粉菌担孢子中3 - O - 甲基葡萄糖的摄取和流出动力学，实验对象包括活性细胞以及代谢活性被叠氮化物和碘乙酸抑制的细胞。结果表明，失能转运系统是由载体介导的，细胞外表观亲和常数（Ko）为13±2 mM，细胞内表观亲和常数（K1）为18±2 mM。同一系统的表观最大速率常数，摄取时（V +）为0.66±0.05 mmol/1细胞水每分钟，流出时（V -）为0.53±0.04 mmol/1细胞水每分钟。对于活性系统，K0 = 0.08±0.01，K1大于40，V + = 9.7±0.5，V - = 1.1±0.9（单位相同）。根据Regen和Morgan（Regen, D.M. and Morgan, H.E. (1964) Biochim. Biophys. Acta 79, 151 - 166）提出的载体机制对这些结果进行了讨论。抗真菌化合物羧菌灵对失能转运无影响，但在活性系统中可降低K0和V +。还发现根皮素和根皮苷对失能细胞无影响，但前者增强而后者抑制活性摄取。
