Matsushita K, Nonobe M, Shinagawa E, Adachi O, Ameyama M
J Bacteriol. 1987 Jan;169(1):205-9. doi: 10.1128/jb.169.1.205-209.1987.
D-Glucose dehydrogenase is a pyrroloquinoline quinone-dependent primary dehydrogenase linked to the respiratory chain of a wide variety of bacteria. The enzyme exists in the membranes of Escherichia coli, mainly as an apoenzyme which can be activated by the addition of pyrroloquinoline quinone and magnesium. Thus, membrane vesicles of E. coli can oxidize D-glucose to gluconate and generate an electrochemical proton gradient in the presence of pyrroloquinoline quinone. The D-glucose oxidase-respiratory chain was reconstituted into proteoliposomes, which consisted of two proteins purified from E. coli membranes, D-glucose dehydrogenase and cytochrome o oxidase, and E. coli phospholipids containing ubiquinone 8. The electron transfer rate during D-glucose oxidation and the membrane potential generation in the reconstituted proteoliposomes were almost the same as those observed in the membrane vesicles when pyrroloquinoline quinone was added. The results demonstrate that the quinoprotein, D-glucose dehydrogenase, can reduce ubiquinone 8 directly within phospholipid bilayer and that the D-glucose oxidase system of E. coli has a relatively simple respiratory chain consisting of primary dehydrogenase, ubiquinone 8, and a terminal oxidase.
D-葡萄糖脱氢酶是一种与多种细菌呼吸链相连的吡咯喹啉醌依赖性初级脱氢酶。该酶存在于大肠杆菌的细胞膜中，主要以脱辅基酶的形式存在，可通过添加吡咯喹啉醌和镁来激活。因此，在吡咯喹啉醌存在的情况下，大肠杆菌的膜囊泡可以将D-葡萄糖氧化为葡萄糖酸盐并产生电化学质子梯度。D-葡萄糖氧化酶-呼吸链被重组到蛋白脂质体中，该蛋白脂质体由从大肠杆菌膜中纯化的两种蛋白质、D-葡萄糖脱氢酶和细胞色素o氧化酶以及含有泛醌8的大肠杆菌磷脂组成。当添加吡咯喹啉醌时，重组蛋白脂质体中D-葡萄糖氧化过程中的电子传递速率和膜电位产生与在膜囊泡中观察到的几乎相同。结果表明，醌蛋白D-葡萄糖脱氢酶可以在磷脂双层内直接还原泛醌8，并且大肠杆菌的D-葡萄糖氧化酶系统具有相对简单的呼吸链，由初级脱氢酶、泛醌8和末端氧化酶组成。
