Kirkman H N, Gaetani G F
Proc Natl Acad Sci U S A. 1984 Jul;81(14):4343-7. doi: 10.1073/pnas.81.14.4343.
Catalases (H2O2:H2O2 oxidoreductase, EC 1.11.1.6) from many species are known to be tetramers of 60,000-dalton subunits, with four heme groups per tetramer. Previous authors have determined the amino acid sequence and three-dimensional structure of bovine liver catalase. Studies of the regulation of the pentose phosphate pathway led the present authors to a search for proteins that bind NADP+ and NADPH in human erythrocytes. An unexpected result of that search was the finding that a major reservoir of bound NADPH in human erythrocytes is catalase. Each tetrameric molecule of human or bovine catalase contains four molecules of tightly bound NADPH. The binding sites have the relative affinities NADPH greater than NADH greater than NADP+ greater than NAD+. NADPH does not seem to be essential for the enzymic conversion of H2O2 to O2 and water but does provide protection of catalase against inactivation by H2O2.
已知许多物种的过氧化氢酶（H2O2：H2O2氧化还原酶，EC 1.11.1.6）是由60,000道尔顿亚基组成的四聚体，每个四聚体含有四个血红素基团。先前的作者已经确定了牛肝过氧化氢酶的氨基酸序列和三维结构。对磷酸戊糖途径调节的研究促使本文作者去寻找人红细胞中结合NADP+和NADPH的蛋白质。该研究的一个意外结果是发现人红细胞中结合NADPH的主要储存库是过氧化氢酶。人或牛过氧化氢酶的每个四聚体分子都含有四个紧密结合的NADPH分子。结合位点对NADPH、NADH、NADP+和NAD+的相对亲和力依次为NADPH＞NADH＞NADP+＞NAD+。NADPH似乎对于过氧化氢酶将H2O2转化为O2和水的酶促反应不是必需的，但确实能保护过氧化氢酶不被H2O2灭活。
