IMPROVED PROCEDURE FOR ASSAY OF GLYCOGEN SYNTHASE AND PHOSPHORYLASE IN RAT-LIVER HOMOGENATES
IMPROVED PROCEDURE FOR ASSAY OF GLYCOGEN SYNTHASE AND PHOSPHORYLASE IN RAT-LIVER HOMOGENATES
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DOI：
10.1016/0003-2697(77)90257-3
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发表时间：
1977-01-01
影响因子：
2.9
通讯作者：
KATZ, J
中科院分区：
文献类型：
--
作者：
GOLDEN, S;WALS, PA;KATZ, J
描述了一种改进的快速分离肝匀浆中糖原合成酶（EC 2.4.1.11）测定中形成的标记糖原的方法。由udp -葡萄糖形成的糖原与磷酸盐化合物和其他电解质通过醋酸或氯化物形式的阴离子交换树脂的小柱分离。流出物含有糖原和其他多糖和糖。当合酶活性较低时，实验中形成的标记糖原约有一半被淀粉酶或葡萄糖苷酶分解，导致常规糖原沉淀方法对活性的低估。阴离子交换树脂的使用避免了这种错误。大鼠肝脏匀浆中30-70%的糖原合成酶以颗粒形式存在于10,000-20,000 g离心的颗粒中。大鼠肝脏匀浆中a和b形式的udp -葡萄糖的表观Km均为0.9 mM。描述了一种快速测定两种形式糖原磷酸化酶的方法，即用离子交换树脂从葡萄糖-磷酸中分离放射性糖原。
An improved rapid procedure for the separation of labeled glycogen formed in the assay of glycogen synthase (EC 2.4.1.11) in liver homogenates is described. The glycogen formed from UDP-glucose is separated from phosphate compounds and other electrolytes by passage through a small column of an anion-exchange resin in the acetate or chloride form. The effluent contains glycogen and other polysaccharides and sugars. When the synthase activity is low about half of the labeled glycogen formed in the assay is broken down by amylases or glucosidases, causing an underestimation of the activity by conventional methods of glycogen precipitation. The use of anion-exchange resin avoids this error. From 30-70% of the a form of glycogen synthase in rat liver homogenates is in a particulate form found in the pellet centrifuged at 10,000-20,000 g. The apparent Km for UDP-glucose, for both the a and b forms in rat liver homogenates is 0.9 mM. A rapid procedure to assay the 2 forms of glycogen phosphorylase by separating radioactive glycogen from glucose 1-phosphate with ion-exchange resins is described.