Studies on Formation of Ketone Bodies
スポンサーリンク
概要
- 論文の詳細を見る
Distribution of acetoacetate-forming activity in rat liver was investigated. It was found that the soluble fraction had an activity comparable to that of mitochondria. When 1, 5-<SUB>14</SUB>C-citrate was incubated with the supernatant fraction, incorporation of <SUB>14</SUB>C into acetoacetate was greatly diminished by addition of an antibody against ATP citrate lyase. This decreased incorporation was completely reversed to the original level by addition of excess purified ATP citrate lyase. This fact suggests that the material utilized for acetoacetate formation, acetyl-CoA, in the supernatant is supplied out of mitochondria via citrate and ATP citrate lyase. Incorporation of U-<SUB>14</SUB>C-palmitate into acetoacetate was also investigated with the reconstructed system which contains both the mitochondria and the supernatant fraction. Mitochondria alone had a remarkable activity to produce acetoacetate from palmitate, while the supernatant alone showed no activity, as this fraction failed to oxidize palmitate into acetyl CoA. However, combination of both fractions significantly increased the acetoacetate formation from palmitate in an amount larger than the sum of the values obtained with each fraction. In addition, the supplement of purified ATP citrate lyase to the reconstructed system strikingly enhanced the incorporation of <SUB>14</SUB>C-palmitate into acetoacetate, the enhanced value being about twice that obtained with the reconstructed system. These results indicate that the supernatant, besides the mitochondria, also plays important roles in the formation of ketone bodies, and that ATP citrate lyase is involved in this reaction. In the supernatant system, addition of unlabelled β-hydroxy-β-methylglutaryl CoA (HMG-CoA) greatly reduces incorporation of 1-<SUB>14</SUB>C-acetyl CoA into acetoacetate. After incubation, HMG-CoA was isolated as HMG and counted. It was shown that a significant radioactivity was found in HMG. Therefore, it is concluded that acetoacetate is formed via HMG-CoA in the liver supernatant system. The significance of the present findings is discussed in relation to cholesterol synthesis.
- Japan Society of Clinical Chemistryの論文
著者
関連論文
- ヒト病的歯肉結合組織成分に関する研究 : II. ウロン酸ならびに可溶性コラーゲンについて
- ヒト病的歯肉結合組織成分に関する研究 : I. ヘキソサミンならびにコラーゲン量について
- A New Method for Determination of Polyamines and Its Application
- Studies on Dextran-Insulin
- Studies on Formation of Ketone Bodies