KMID : 0351619750160010251
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Kyungpook Medical Journal 1975 Volume.16 No. 1 p.251 ~ p.260
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Purification and Properties of Phosphoenolpyruvate Carboxykinase from Chicken Liver
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Abstract
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Phosphoenolpyruvate carboxykinase(EC 4.1.1.32) has been isolated from the mitochondria of chicken liver and purified 450-fald from the initial crude mitochondrial extract in 20% yield. The specific activity of purified enzyme was found to be 1205 micro moles of 14C-oxaloacetate formed per min per mg of protein at 30 by oxaloacetate-H14CO3¢¥ exchange assay. The enzyme showed the molecular weight of 24, 000 by the Sephadex G-75 gel filtration method and the isoelectric point of 4.95 io 5, 05 by a isoel~ctric focusing technique. ¢¥,the optimal pH and temperature were 6.9 to 7.1 and 30 to 35, respectively. Michaelis constants for PEP and GDP in the carboxylation reaction are 5.2 to 3,5X10-~M and 2.1 to 3.3X10¢¥M, :respectively, and that for oxaloacetate and GTP in the exchange reaction were similar to the values of PEP and GDP. This enzyme was comperatively tolerate to the heat, and kept the activity for 3 months.
The mitochondria of chicken liver contained high levels of Phosphoenolpyruvate carboxykinase, therefores it seems to be a good source of emzyme purificaltion.
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