SOME CHARACTERISTICS OF BRAIN TYROSINE HYDROXYLASE
SOME CHARACTERISTICS OF BRAIN TYROSINE HYDROXYLASE
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DOI：
10.1139/o67-185
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发表时间：
1967-01-01
期刊：
影响因子：
--
通讯作者：
MCGEER, PL
中科院分区：
文献类型：
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作者：
MCGEER, EG;GIBSON, S;MCGEER, PL
来自脑匀浆的酪氨酸羟化酶与来自肾上腺匀浆的酪氨酸羟化酶的不同之处在于颗粒结合，对辅因子不敏感，具有较低的酪氨酸米氏常数，并且对pH和缓冲液的略微不同的最佳条件有反应。0.02 [image]巯基乙醇和0.1-1.0 m[image] 2-氨基-4-羟基-6，7-二甲基四氢蝶啶（DMPH 4）的组合使牛肾上腺匀浆中的酪氨酸羟化酶活性增加15倍，但对大鼠脑匀浆中的酪氨酸羟化酶活性没有影响。牛肾上腺匀浆中酪氨酸的Km为4 x 105 [image]，大鼠脑匀浆中为0.45 x 105 [image]，牛肾上腺匀浆中的转化率在0.6 [image]醋酸钠缓冲液（pH 6.0）中最大，大鼠脑匀浆中的转化率在0.28 [image]磷酸盐缓冲液（pH 6.2）中最大。
Tyrosine hydroxylase from brain homogenates differed from tyrosine hydroxylase from adrenal homogenates in being particle-bound, insensitive to cofactors, possessing a lower Michaelis constant for tyrosine, and being responsive to slightly different optimum conditions of pH and buffer. The combination of 0.02 [image] mercaptoethanol and 0.1-1.0 m[image] 2-amino-4-hydroxy-6,7-dimethyltetrahydropteridine (DMPH4) increase tyrosine hydroxylase activity in beef adrenal homogenates 15-fold, but was without effecton activity in rat brain homogenates. The Km for tyrosine in beef adrenal homogenates was 4 x 105 [image], and in rat brain homogenates was 0.45 x 105 [image], Conversion in beef adrenal homogenates was maximum in 0.6 [image] sodium acetate buffer, pH 6.0, and in rat brain homogenates was maximum in 0.28 [image] phosphate buffer, pH 6.2.