Raz A, Aharony D
Res Commun Chem Pathol Pharmacol. 1978 Sep;21(3):507-15.
Double-labeled [3H/14C]-prostaglandin endoperoxide H2 was used to assess the presence in platelets of enzymatic activity for conversion of the endoperoxides to prostaglandin E2. This enzymatic activity (prostaglandin H2 leads to E2 isomerase) involves the selective removal of a hydrogen from the C-9 carbon atom of the endoperoxide molecule and is subject to an isotope discriminatory effect against tritium-labeled molecules. Rabbit washed platelet suspension was pre-incubated for 1 min, with imidazole (1 mM) to inhibit thromboxane A2 generation and [3H/14C]--prostaglandin H2 was added. Analysis of the [3H] and [14C] radioactive products in incubations with native vs. heat denatured platelets indicated that native platelets convert the endoperoxide enzymatically to mainly prostaglandin E2. Thus, although arachidonic acid released endogenously or added exogenously to platelets is converted mainly to thromboxane B2 and 120H-17:3 acid, platelets appear to possess prostaglandin H2 leads to E2 isomerase activity which becomes manifested when thromboxane synthetase activity is inhibited.
使用双标记的[3H/14C] - 前列腺素内过氧化物H2来评估血小板中存在将内过氧化物转化为前列腺素E2的酶活性。这种酶活性（前列腺素H2转化为E2异构酶）涉及从内过氧化物分子的C-9碳原子上选择性去除一个氢，并且对氚标记的分子存在同位素歧视效应。将兔洗涤血小板悬液用咪唑（1 mM）预孵育1分钟以抑制血栓素A2的生成，然后加入[3H/14C] - 前列腺素H2。对天然血小板与热变性血小板孵育中的[3H]和[14C]放射性产物的分析表明，天然血小板可将内过氧化物酶促转化为主要是前列腺素E2。因此，尽管内源性释放或外源性添加到血小板中的花生四烯酸主要转化为血栓素B2和12-羟基-17:3酸，但血小板似乎具有前列腺素H2转化为E2异构酶活性，当血栓素合成酶活性受到抑制时该活性会表现出来。
