大肠杆菌中延胡索酸还原酶系统产生的电化学质子梯度及其生物能量学意义。

The electrochemical proton gradient generated by the fumarate-reductase system in Escherichia coli and its bioenergetic implications.

作者信息

Hellingwerf K J, Bolscher J G, Konings W N

出版信息

Eur J Biochem. 1981 Jan;113(2):369-74. doi: 10.1111/j.1432-1033.1981.tb05075.x.

DOI:10.1111/j.1432-1033.1981.tb05075.x

Abstract

Proton translocation, coupled to electron transfer in the fumarate reductase system, generates and electrochemical potential gradient for protons (delta approximately mu H+). The magnitude of this free energy gradient has been determined in the Escherichia coli strains ML 208-225 and AN 283. The measurements were performed in (inverted) membrane particles, right-side out membrane vesicles and EDTA-treated intact cells in external media of various ionic compositions and pH. The maximal values of delta approximately mu H+ in these three systems were +103, -101 and -105 mV, respectively. This implicates that in E. coli, upon transition from oxygen to fumarate as electron acceptor, the magnitude of the delta approximately mu H+ decreases considerably. This change of delta approximately mu H+ has substantial consequences for the cellular metabolism.

摘要

在延胡索酸还原酶系统中，质子转运与电子传递相偶联，产生质子的电化学势梯度（ΔμH⁺）。已在大肠杆菌菌株ML 208 - 225和AN 283中测定了这种自由能梯度的大小。测量是在（倒置的）膜颗粒、外翻膜囊泡以及经乙二胺四乙酸（EDTA）处理的完整细胞中进行的，这些细胞处于具有不同离子组成和pH值的外部介质中。在这三个系统中，ΔμH⁺的最大值分别为 +103、 -101和 -105 mV。这表明在大肠杆菌中，当电子受体从氧气转变为延胡索酸时，ΔμH⁺的大小会显著降低。ΔμH⁺的这种变化对细胞代谢具有重大影响。