TRANSPORT OF HEMICELLULOSE MONOMERS IN THE XYLOSE-FERMENTING YEAST CANDIDA-SHEHATAE
TRANSPORT OF HEMICELLULOSE MONOMERS IN THE XYLOSE-FERMENTING YEAST CANDIDA-SHEHATAE
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DOI：
10.1007/bf02346066
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发表时间：
1986-03-01
影响因子：
5
通讯作者：
VANUDEN, N
中科院分区：
文献类型：
--
作者：
LUCAS, C;VANUDEN, N
在葡萄糖或D-木糖培养基中生长受到抑制的休哈塔假丝酵母细胞产生一种易化扩散系统，该系统转运葡萄糖（Ks. ±. 2 mM，Vmax ±。2.3 mmol g-1 h-1）、D-木糖（Ks. ±. 125 mM，Vmax ±。22.5 mmol g-1 h-1）和D-甘露糖，但既不含D-半乳糖也不含L-阿拉伯糖。饥饿解除抑制的细胞形成几个糖质子共转运体。一个质子共转运体积累约400倍的3 - 0-甲基葡萄糖和运输葡萄糖（Ks. ±-. 0.12 mM，Vmax ±。3.2 mmoles g-1 h-1）和D-甘露糖，第二个质子同向转运体转运D-木糖（Ks. ±. 1.0 mM，Vmax 1.4 mmol g-1 h-1）和D-半乳糖，而L-阿拉伯糖显然使用第三个质子同向转运。化学计量是每个葡萄糖或D-木糖分子转运一个质子。底物的糖质子共运输抑制非竞争性的其他共运输的基板。饥饿，而诱导的糖-质子共运输，沉默的促进扩散系统相对于葡萄糖的运输，但不是相对于D-木糖的运输，促进扩散功能的同时与D-木糖-质子共运输。
Cells of Candida shehatae repressed by growth in glucose- or D-xylose-medium produced a facilitated diffusion system that transported glucose (Ks .+-. 2 mM, Vmax .+-. 2.3 mmoles g-1 h-1), D-xylose (Ks .+-. 125 mM, Vmax .+-. 22.5 mmoles g-1 h-1) and D-mannose, but neither D-galactose nor L-arabinose. Cells derepressed by starvation formed several sugar-proton symports. One proton symport accumulated 3-0-methylglucose about 400-fold and transported glucose (Ks .+-. 0.12 mM, Vmax .+-. 3.2 mmoles g-1 h-1) and D-mannose, a second proton symport transported D-xylose (Ks .+-. 1.0 mM, Vmax 1.4 mmoles g-1 h-1) and D-galactose, while L-arabinose apparently used a third proton symport. The stoicheiometry was one proton for each molecule of glucose or D-xylose transported. Substrates of one sugar proton symport inhibited non-competitively the transport of substrates of the other symports. Starvation, while inducing the sugar-proton symports, silenced the facilitated diffusion system with respect to glucose transport but not with respect to the transport of D-xylose, facilitated diffusion functioning simultaneously with the D-xylose-proton symport.