脊椎动物和无脊椎动物肌肉中丙酮酸羧化酶、磷酸烯醇式丙酮酸羧化酶和果糖二磷酸酶的活性。

The activities of pyruvate carboxylase, phosphoenolpyruvate carboxylase and fructose diphosphatase in crude homogenates of vertebrate and invertebrate muscles are reported. 2. Pyruvate carboxylase activity was present in all insect flight muscles that were investigated: in homogenates of bumble-bee flight muscle the activity was inhibited by ADP and activated by acetyl-CoA, and it was distributed mainly in the mitochondrial fraction. This is the first demonstration of pyruvate carboxylase activity in muscle. However, the activity appears to be restricted to insect flight muscle, since it was not found in other invertebrate or vertebrate muscles. 3. Since the three enzymes were never found together in the same muscle, it is concluded that these enzymes cannot provide a pathway for the synthesis of glycogen from lactate or pyruvate in muscle. Other roles for these enzymes in muscle are suggested. In particular, pyruvate carboxylase may be present in insect flight muscle for the provision of oxaloacetate to support the large increase in activity of the tricarboxylic acid cycle which occurs when an insect takes flight.

本文报道了脊椎动物和无脊椎动物肌肉粗匀浆中丙酮酸羧化酶、磷酸烯醇丙酮酸羧化酶和果糖二磷酸酶的活性。2. 在所有被研究的昆虫飞行肌中均存在丙酮酸羧化酶活性：在大黄蜂飞行肌匀浆中，该活性受ADP抑制，被乙酰辅酶A激活，且主要分布在线粒体部分。这是首次在肌肉中证实丙酮酸羧化酶活性。然而，该活性似乎仅限于昆虫飞行肌，因为在其他无脊椎动物或脊椎动物肌肉中未发现。3. 由于这三种酶从未在同一块肌肉中同时被发现，因此得出结论，这些酶无法为肌肉中由乳酸或丙酮酸合成糖原提供途径。文中提出了这些酶在肌肉中的其他作用。特别是，丙酮酸羧化酶可能存在于昆虫飞行肌中，用于提供草酰乙酸以支持昆虫飞行时三羧酸循环活性的大幅增加。

The activities of pyruvate carboxylase, phosphoenolpyruvate carboxylase and fructose diphosphatase in muscles from vertebrates and invertebrates.