Kotyk A, Dvoráková M
Department of Membrane Transport, Czechoslovak Academy of Sciences, Prague, Czech and Slovak Federal Rep.
Biochim Biophys Acta. 1992 Mar 2;1104(2):293-8. doi: 10.1016/0005-2736(92)90043-l.
Transport of amino acids in Saccharomyces cerevisiae is an H(+)-driven secondary active transport. Inhibitors of the plasma membrane H(+)-ATPase, particularly heavy water, diethylstilbestrol and suloctidil, were shown to affect the H(+)-extruding ATPase activity as well as the ATP-hydrolyzing activity, to a similar degree as they inhibited the transport of amino acids. The inhibitors had virtually no effect on the membrane electric potential or on the delta pH which constitute the thermodynamically relevant source of energy for these transports. Transport of acidic amino acids was affected much more than that of the neutral and especially of the basic ones. The effects were greater with higher amino acid concentrations. All this is taken as evidence that the amino acid carriers respond kinetically to the presence of protons directly at the membrane site where they are extruded by the H(+)-ATPase, rather than to the overall protonmotive force.
酿酒酵母中氨基酸的转运是一种由H⁺驱动的继发性主动转运。质膜H⁺ -ATP酶的抑制剂，特别是重水、己烯雌酚和舒洛地尔，已被证明会影响H⁺ 外排ATP酶活性以及ATP水解活性，其程度与它们抑制氨基酸转运的程度相似。这些抑制剂对构成这些转运的热力学相关能量来源的膜电位或ΔpH几乎没有影响。酸性氨基酸的转运比中性氨基酸，尤其是碱性氨基酸的转运受到的影响要大得多。氨基酸浓度越高，影响越大。所有这些都被视为证据，表明氨基酸载体在动力学上直接对质子在膜位点的存在做出反应，在该位点质子由H⁺ -ATP酶排出，而不是对整体质子动力做出反应。
