正常和四氧嘧啶糖尿病绵羊组织中肉碱与辅酶A酯的关系

Relationships between carnitine and coenzyme A esters in tissues of normal and alloxan-diabetic sheep.

作者信息

Snoswell A M, Koundakjian P P

出版信息

Biochem J. 1972 Mar;127(1):133-41. doi: 10.1042/bj1270133.

DOI:10.1042/bj1270133

PMID:5073738

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1178568/

Abstract

The total acid-soluble carnitine concentrations of four tissues from Merino sheep showed a wide variation not reported for other species. The concentrations were 134, 538, 3510 and 12900nmol/g wet wt. for liver, kidney cortex, heart and skeletal muscle (M. biceps femoris) respectively. 2. The concentration of acetyl-CoA was approximately equal to the concentration of free CoA in all four tissues and the concentration of acid-soluble CoA (free CoA plus acetyl-CoA) decreased in the order liver>kidney cortex>heart>skeletal muscle. 3. The total amount of acid-soluble carnitine in skeletal muscle of lambs was 40% of that in the adult sheep, whereas the concentration of acid-soluble CoA was 2.5 times as much. A similar inverse relationship between carnitine and CoA concentrations was observed when different muscles in the adult sheep were compared. 4. Carnitine was confined to the cytosol in all four tissues examined, whereas CoA was equally distributed between the mitochondria and cytosol in liver, approx. 25% was present in the cytosol in kidney cortex and virtually none in this fraction in heart and skeletal muscle. 5. Carnitine acetyltransferase (EC 2.3.1.7) was confined to the mitochondria in all four tissues and at least 90% of the activity was latent. 6. Acetate thiokinase (EC 6.2.1.1) was predominantly (90%) present in the cytosol in liver, but less than 10% was present in this fraction in heart and skeletal muscle. 7. In alloxan-diabetes, the concentration of acetylcarnitine was increased in all four tissues examined, but the total acid-soluble carnitine concentration was increased sevenfold in the liver and twofold in kidney cortex. 8. The concentration of acetyl-CoA was approximately equal to that of free CoA in the four tissues of the alloxan diabetic sheep, but the concentration of acid-soluble CoA in liver increased approximately twofold in alloxan-diabetes. 9. The relationship between CoA and carnitine and the role of carnitine acetyltransferase in the various tissues is discussed. The quantitative importance of carnitine in ruminant metabolism is also emphasized.

摘要

美利奴羊四种组织中酸溶性肉碱的总浓度呈现出较大差异，其他物种未见此报道。肝脏、肾皮质、心脏和骨骼肌（股二头肌）的浓度分别为134、538、3510和12900nmol/g湿重。2. 所有四种组织中乙酰辅酶A的浓度大致等于游离辅酶A的浓度，酸溶性辅酶A（游离辅酶A加乙酰辅酶A）的浓度按肝脏>肾皮质>心脏>骨骼肌的顺序降低。3. 羔羊骨骼肌中酸溶性肉碱的总量是成年羊的40%，而酸溶性辅酶A的浓度是成年羊的2.5倍。比较成年羊的不同肌肉时，也观察到了肉碱和辅酶A浓度之间类似的反比关系。4. 在所有检测的四种组织中，肉碱局限于胞质溶胶中，而辅酶A在肝脏的线粒体和胞质溶胶中分布均匀，在肾皮质中约25%存在于胞质溶胶中，在心脏和骨骼肌的该部分中几乎不存在。5. 肉碱乙酰转移酶（EC 2.3.1.7）在所有四种组织中都局限于线粒体，且至少90%的活性是潜在的。6. 乙酸硫激酶（EC 6.2.1.1）在肝脏中主要（90%）存在于胞质溶胶中，但在心脏和骨骼肌的该部分中不到10%。7. 在四氧嘧啶糖尿病中，所有检测的四种组织中乙酰肉碱的浓度都升高了，但肝脏中酸溶性肉碱的总浓度升高了7倍，肾皮质中升高了2倍。8. 四氧嘧啶糖尿病绵羊的四种组织中乙酰辅酶A的浓度大致等于游离辅酶A的浓度，但在四氧嘧啶糖尿病中肝脏中酸溶性辅酶A的浓度大约升高了2倍。9. 讨论了辅酶A与肉碱之间的关系以及肉碱乙酰转移酶在各种组织中的作用。还强调了肉碱在反刍动物代谢中的定量重要性。