Nakashima Yumiko, Shinzawa-Itoh Kyoko, Watanabe Kenji, Naoki Kazuki, Hano Nobuko, Yoshikawa Shinya
Department of Life Science, Himeji Institute of Technology and CREST, Japan Science and Technology Corporation, Kamigohri, Akoh Hyogo.
J Bioenerg Biomembr. 2002 Feb;34(1):11-9. doi: 10.1023/a:1013862502185.
Steady-state kinetics of the bovine heart NADH:coenzyme Q oxidoreductase reaction were analyzed in the presence of various concentrations of NADH and coenzyme Q with one isoprenoid unit (Q1). Product inhibitions by NAD+ and reduced coenzyme Q1 were also determined. These results show an ordered sequential mechanism in which the order of substrate binding and product release is Q1-NADH-NAD+-Q1H2. It has been widely accepted that the NADH binding site is likely to be on the top of a large extramembrane portion protruding to the matrix space while the Q1 binding site is near the transmembrane moiety. The rigorous controls for substrate binding and product release are indicative of a strong, long range interaction between NADH and Q1 binding sites.
在存在不同浓度的NADH和带有一个异戊二烯单元的辅酶Q（Q1）的情况下，分析了牛心NADH：辅酶Q氧化还原酶反应的稳态动力学。还测定了NAD⁺和还原型辅酶Q1的产物抑制作用。这些结果显示了一种有序的顺序机制，其中底物结合和产物释放的顺序为Q1-NADH-NAD⁺-Q1H2。人们普遍认为，NADH结合位点可能位于突出到基质空间的大的膜外部分的顶部，而Q1结合位点靠近跨膜部分。对底物结合和产物释放的严格控制表明NADH和Q1结合位点之间存在强烈的、长程相互作用。
