骨骼肌中亮氨酸的部分氧化。

Partial oxidation of leucine in skeletal muscle.

Palmer T N, Gossain S, Sugden M C

Department of Biochemistry, University of Western Australia, Nedlands.

Biochem Mol Biol Int. 1993 Feb;29(2):255-62.

Abstract

Leucine and its 2-oxo analogue, 4-methyl-2-oxopentanoate, increased the release of acetoacetate and 3-hydroxybutyrate from hemidiaphragms isolated from 40 h-starved rats. Glucose and lactate+pyruvate decreased basal and leucine-stimulated rates of ketone body production. 2. The production of acetoacetate + 3-hydroxybutyrate in response to addition of leucine was suppressed in hemidiaphragms from fed rats. 3. At 3 mM leucine, for each mumol of leucine oxidized in the branched-chain 2-oxo acid dehydrogenase reaction (measured as 14CO2 production from [1-14C]leucine), 0.84 mumol of acetoacetate + 3-hydroxybutyrate were produced. This stoichiometry may imply that acetoacetate derived from the partial oxidation of leucine is not further oxidized in situ. The physiological significance of these findings is discussed.

摘要

亮氨酸及其2-氧代类似物4-甲基-2-氧代戊酸酯，增加了从饥饿40小时的大鼠分离出的半膈中乙酰乙酸和3-羟基丁酸的释放。葡萄糖和乳酸+丙酮酸降低了酮体生成的基础速率和亮氨酸刺激的速率。2. 喂食大鼠的半膈中，添加亮氨酸后乙酰乙酸+3-羟基丁酸的生成受到抑制。3. 在3 mM亮氨酸浓度下，在支链2-氧代酸脱氢酶反应中每氧化1 μmol亮氨酸（以[1-14C]亮氨酸产生的14CO2量来衡量），会产生0.84 μmol乙酰乙酸+3-羟基丁酸。这种化学计量关系可能意味着源自亮氨酸部分氧化的乙酰乙酸不会在原位进一步氧化。讨论了这些发现的生理意义。