Ruf H H, Schuhn D, Dietz R, Nastainczyk W, Nielsen M
Medizintechnik, Fraunhofer-Gesellschaft und Universität des Saarlandes, St. Ingbert, Federal Republic of Germany.
Eur J Biochem. 1992 Mar 15;204(3):1069-73. doi: 10.1111/j.1432-1033.1992.tb16730.x.
To determine the size of the functional catalytic unit of prostaglandin endoperoxide (prostaglandin H) synthase, radiation inactivation experiments were performed. Both microsomes from ovine seminal vesicles and purified enzyme were irradiated with 10 MeV electrons. The enzymic activities of prostaglandin H synthase, cyclooxygenase and peroxidase, showed mono-exponential inactivation curves dependent on radiation dose, indicating molecular masses of approximately 72 kDa. The enzyme in microsomes, in its native environment, as well as in its purified state after solubilisation with nonionic detergent showed identical molecular masses. The results clearly demonstrate that the monomer of the enzyme with an apparent molecular mass of 72 kDa (SDS/PAGE) is the functional unit for catalysis of both activities. Hence the two active sites of cyclooxygenase and peroxidase reside on the same polypeptide chain.
为了确定前列腺素内过氧化物（前列腺素H）合酶的功能性催化单位的大小，进行了辐射失活实验。用10 MeV电子对来自绵羊精囊的微粒体和纯化的酶进行辐照。前列腺素H合酶、环氧化酶和过氧化物酶的酶活性呈现出依赖于辐射剂量的单指数失活曲线，表明其分子量约为72 kDa。微粒体中的酶在其天然环境中，以及在用非离子去污剂溶解后的纯化状态下，显示出相同的分子量。结果清楚地表明，表观分子量为72 kDa（SDS/PAGE）的酶单体是催化这两种活性的功能单位。因此，环氧化酶和过氧化物酶的两个活性位点位于同一条多肽链上。
