人类中性粒细胞产生O2的氧化还原酶：催化活性表达对钙和镁有绝对需求的证据。
The O2- generating oxidoreductase of human neutrophils: evidence of an obligatory requirement for calcium and magnesium for expression of catalytic activity.
作者信息
Green T R, Wu D E, Wirtz M K
出版信息
Biochem Biophys Res Commun. 1983 Feb 10;110(3):973-8. doi: 10.1016/0006-291x(83)91058-6.
NADPH-dependent O2- generating oxidoreductase activity recovered from cell lysates of phorbol myristate acetate-stimulated human neutrophils exhibits dependence on Ca+2 and Mg+2 for full expression of its catalytic activity. O2- generating activity was completely abolished by exposure of the oxidoreductase to EDTA, then reconstituted by exposure of the enzyme to Ca+2 and Mg+2 in excess of the EDTA concentration used to block catalytic activity. The oxidoreductase responded maximally to either 0.25 mM Ca+2 or 0.80 mM Mg+2. The pH optimum of the oxidoreductase exposed to Ca+2 and Mg+2 is between pH 7.0 and 7.6. The molar ratio of NADPH oxidation to O2- production determined at pH 7.6 in the presence of Ca+2 and Mg+2 is 0.49, indicating 1 mole of NADPH oxidized per 2 moles of O2- formed. Particulate fractions recovered from cell lysates of resting neutrophils exhibited no oxidoreductase activity under the same conditions.
从佛波醇肉豆蔻酸酯乙酸酯刺激的人中性粒细胞的细胞裂解物中恢复的依赖烟酰胺腺嘌呤二核苷酸磷酸（NADPH）的产超氧阴离子（O₂⁻）氧化还原酶活性，其催化活性的充分表达依赖于钙离子（Ca²⁺）和镁离子（Mg²⁺）。将氧化还原酶暴露于乙二胺四乙酸（EDTA）会使产O₂⁻活性完全丧失，然后通过将酶暴露于超过用于阻断催化活性的EDTA浓度的Ca²⁺和Mg²⁺中使其活性恢复。氧化还原酶对0.25 mM Ca²⁺或0.80 mM Mg²⁺的反应最大。暴露于Ca²⁺和Mg²⁺的氧化还原酶的最适pH在7.0至7.6之间。在存在Ca²⁺和Mg²⁺的情况下于pH 7.6测定的NADPH氧化与O₂⁻产生的摩尔比为0.49，表明每形成2摩尔O₂⁻氧化1摩尔NADPH。在相同条件下，从静息中性粒细胞的细胞裂解物中回收的颗粒级分未表现出氧化还原酶活性。
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