STEROL METABOLISM .19. BIOSYNTHESIS OF CHOLEST-5-ENE-3BETA, 24-DIOL (CEREBROSTEROL) BY BOVINE CEREBRAL CORTICAL MICROSOMES
STEROL METABOLISM .19. BIOSYNTHESIS OF CHOLEST-5-ENE-3BETA, 24-DIOL (CEREBROSTEROL) BY BOVINE CEREBRAL CORTICAL MICROSOMES
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DOI：
10.1111/j.1471-4159.1973.tb04224.x
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发表时间：
1973-01-01
影响因子：
4.7
通讯作者：
SMITH, LL
中科院分区：
文献类型：
--
作者：
DHAR, AK;TENG, JI;SMITH, LL
通过从人脑、牛脑和兔脑中分离并通过物理性质的比较鉴定，证实了人脑、牛脑和兔脑中存在胆甾醇-5-烯-3-β，24-二醇(脑甾醇)。胆甾烯-5-烯-3-β，24-二醇在人脑中的含量为66.5sg/g，在牛脑中为42.9sg/g，在兔脑中为89.5pg/g。Cholest-5-ene-3β，24-diol是这些脑组织中唯一容易检测到的羟基胆固醇衍生物，集中在人和牛大脑皮层的105,000克颗粒(微体部分)中，核或线粒体部分中没有明显数量的甾醇存在。[1，2-~3H]-或[4-14C]-胆固醇与来自牛大脑皮层匀浆的105,000克微球孵育，结果显示0.1-0.38%的转化率为放射性胆甾烯-5-烯-3β，24-二醇，分离和纯化为3-β，24-二苯甲酸酯。生物转化需要氧气，添加NADPH2对羟化有促进作用。我们的观察证实，在牛大脑皮层中存在一个类固醇24-羟基酶系统。
The presence of cholest‐5‐ene‐3β, 24‐diol (cerebrosterol) in samples of human, bovine, and rabbit brains has been established by isolation of the sterol therefrom and identification by comparison of physical properties. Cholest‐5‐ene‐3β, 24‐diol was present at the level of 66.5 sg/g of dried tissue in human brain, 42.9 μg/g in cattle brain, and 89.5 pg/g in rabbit brain. Cholest‐5‐ene‐3β, 24‐diol was the only readily detectable hydroxycholesterol derivative in these brain tissues and was concentrated in the 105,000 g pellet (microsomal fraction) of both human and bovine cerebral cortex, with no demonstrable amounts of the sterol present in nuclear or mitochondrial fractions. Incubation of [1,2‐3H]‐ or of [4‐14C]‐cholesterol with the 105,000 g microsomal pellet from bovine cerebral cortical homogenates demonstrated 0.1‐0.38 per cent conversions to radioactive cholest‐5‐ene‐3β, 24‐diol, isolated and purified as the 3β, 24‐dibenzoate. The bioconversion required oxygen, and a stimulation of hydroxylation by added NADPH2was demonstrated. Our observations establish that a sterol 24‐hydroxylase system is present in bovine cerebral cortex.