FATTY ACID AND KETONE BODY METABOLISM--ENZYME ISOLATION

这一建议是我们有关隔离的研究的继续 肝微粒体脂肪酸链延长系统的组成部分。 我们最近发现的微粒体短链脂肪酸减少 催化反应的系统，这些反应与 长链脂肪酸延长体系，取得了分离 组件不是简单的任务，并使我们意识到不断增加的 肝内质网的复杂性。 我们的主要重点将是 这两个系统的分离，即，分离两 β-酮酰基辅酶A还原酶（短链β-酮还原酶， 已经将乙酰乙酰辅酶A还原酶与长链β-酮 利用β-酮棕榈酰CoA或β-酮硬脂酰CoA的还原酶 作为底物），分离两种酶和两种反式-2， 3-烯酰辅酶A还原酶。 单个组分酶的纯化 将是我们持续的目标，其次是重建短链 长链系统。 细胞色素b5，其黄素蛋白 短链还原酶中的NADPH还原酶和细胞色素P-450还原酶 将评估系统;磷脂和其他脂质的作用将 也被调查。 该提案的另一个主要目标是 阐明微粒体脂肪酸和脂肪酸的调节或调节 链延长系统和短链酰基辅酶A还原系统。 到 为此，我们将确定饮食因素，糖尿病，胰岛素， 和胰高血糖素控制这两个系统。 糖尿病动物可以 在确定我们的生理重要性方面尤其重要。 新发现的短链酰基辅酶A还原系统，因为一个重要的 该酶系统底物是乙酰乙酰辅酶A，一种酮体 先驱 最后，使用药物，如氯贝丁酯 消胆胺可降低血脂， 这两个微粒体系统 我们的建议将大大有助于 我们对脂质代谢的理解。

This proposal is a continuation of our studies concerned with the isolation of components of the liver microsomal fatty acid chain elongation system. Our recent discovery of a microsomal short chain fatty acid reduction system which catalyzes reactions that are identical to those found in the long chain fatty acid elongation system, has made the separation of components no simple task, and has made us aware of the ever increasing complexity of the liver endoplasmic reticulum. Our primary focus will be the separation of these two systems, i.e., the separation of the two Beta-keto acyl CoA reductases (the short-chain Beta-keto reductase which we have called acetoacetyl CoA reductase versus the long chain Beta-keto reductase which utilizes Beta-ketopalmitoyl CoA or Beta-keto stearoyl CoA as substrates), separation of the two dehydratases and the two trans-2, 3-enoyl CoA reductases. Purification of the individual component enzymes will be our continued goal, followed by reconstitution of the short-chain and long-chain systems. A role for cytochrome b5, its flavoprotein reductase and NADPH cytochrome P-450 reductase in the short chain reductase system will be assessed; the role of phospholipid and other lipids will also be investigated. Another major goal of the proposal is the elucidation of regulation or modulation of both the microsomal fatty acid chain elongation system and the short chain acyl CoA reduction system. To this end, we will determine the role of dietary factors, diabetes, insulin, and glucagon in the control of these two systems. The diabetic animal may be especially important in determining the physiological importance of our newly discovered short-chain acyl CoA reduction system, since an important substrate of this enzyme system is acetoacetyl CoA, a ketone body precursor. Finally, do pharmacologic agents, like clofibrate cholestyramine which induce hypolipidemia exert a significant effect on these two microsomal systems? Our proposal should contribute significantly to our understanding of lipid metabolism.