A lipoxygenase inhibitor in the cytosolic fraction of human epidermoid carcinoma A431 cells was characterized and purified. The cytosolic inhibitor lost the inhibitory activity upon heating at 75 degrees C for 15 min or pretreating with 1 mg/ml trypsin at 37 degrees C for 60 min. Cytosol, after dialysis, lost the inhibitory activity but its inhibitory activity recovered when 1 mM GSH was added to the dialysate. The inhibitory activity of cytosol was also abolished by treatment either with 1 mM iodoacetate at 4 degrees C for 1 h or with 0.5 mM H2O2. The pI of the inhibitor was approx. 7.0. In addition to 12-lipoxygenase, the inhibitor inhibited the activities of 5-lipoxygenase and fatty acid cyclo-oxygenase in a cell-free system. The inhibitor was purified by a series of column chromatographies using CM Sephadex C-50, Sephadex G-100 SF and Mono P columns. A major 22 kDa protein was obtained that was distinct from selenium-dependent glutathione peroxidase.
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机译：表征和纯化了人表皮样癌A431细胞胞质中的脂氧合酶抑制剂。在75摄氏度下加热15分钟或在37摄氏度下用1 mg / ml胰蛋白酶预处理60分钟后，胞质抑制剂丧失了抑制活性。透析后，细胞液丧失了抑制活性，但是当向透析液中加入1 mM GSH时，其抑制活性得以恢复。通过在4摄氏度下用1 mM碘乙酸盐处理1 h或用0.5 mM H2O2处理，也消除了胞浆的抑制活性。抑制剂的pI约为。 7.0。除12-脂氧合酶外，该抑制剂还可以在无细胞系统中抑制5-脂氧合酶和脂肪酸环氧化酶的活性。通过一系列色谱柱（使用CM Sephadex C-50，Sephadex G-100 SF和Mono P柱）纯化抑制剂。获得了主要的22 kDa蛋白，该蛋白不同于硒依赖性谷胱甘肽过氧化物酶。
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