MECHANISMS THAT REGULATE ENZYMES THAT METABOLIZE CIS UNSATURATED FATTY ACIDS

工作总结：目标是加深对 花生四烯酸代谢的生化机制 和亚油酸 这些酶。一氧化氮(NO)被报道可促进前列腺素 通过增强PGHS活性而形成。我们发现NO是一种 为PGHS-1和-2的过氧化物酶底物，但它不能增强 体外环氧合酶活性。在巨噬细胞中，NO不能刺激 PGHS的表达或ALTER依赖于内毒素的PGHS-2的表达。 此外，NO不能促进完整细胞中前列腺素的形成。 我们认为，过氧亚硝酸盐是NO和超氧化物的反应产物 氧化物对此负有责任。其他对PGHS-1的研究表明，酪氨酸 形成的自由基可能是引发反应的中间产物 花生四烯酸氧化。最近，我们已经证明了没有反应 用酪氨酰基将该基团转化为新基团 经ESR分析表征为亚氨氧基。这导致了 硝基酪氨酸的形成，它通常被用作 氧化应激。花生四烯酸和亚油酸的代谢 是在几个人类乳腺细胞系中进行的研究。亚油酸是 BT-20乳腺细胞经血清处理后代谢为13(S)-HpODE 有TGFa的饥饿细胞。分子和序列分析证实 人15-脂氧合酶在这些细胞中的存在。自2013年以来(S)-HpODE上涨- 调节EGFR途径，这些发现表明15- 脂肪氧合酶在调节乳腺细胞生长中的作用。了解 调节酶活性和表达的生化机制 这些酶将为潜在的控制或 预防这些疾病状况。

Summary of Work: The goal is to develop an understanding of the biochemical mechanisms responsible for the metabolism of arachidonic acid and linoleic acid by these enzymes. Nitric oxide (NO) is reported to enhance prostaglandin formation by enhancement of PGHS activity. We found that NO is a substrate for the peroxidase of PGHS-1 and -2 but it does not enhance the cyclooxygenase activity in vitro. In macrophages, NO does not stimulate the expression of PGHS or alter LPS dependent PGHS-2 expression. Furthermore, NO did not enhance prostaglandin formation in intact cells. We propose that peroxynitrite, a reaction product of NO and superoxide oxide is responsible. Other studies with PGHS-1 indicate that a tyrosyl radical is formed which could be the reactive intermediate that initiates arachidonic acid oxygenation. Recently, we have shown that NO reacts with the tyrosyl radical converting the radical to a new radical characterized by ESR analysis as an iminoxyl radical. This leads to the formation of nitrotyrosine which is often used as an indicator of oxidative stress. The metabolism of arachidonic acid and linoleic acid was studies in several human breast cell lines. Linoleic acid was metabolized to 13(S)-HpODE by BT-20 breast cells after treatment of serum starved cells with TGFa. Molecular and sequence analysis confirm the presence of human15-lipoxygenase in these cells. Since 13(S)-HpODE up- regulates the EGFR pathway, these findings suggest a role of 15- lipoxygenase in the regulation of breast cell growth. Understanding the biochemical mechanisms which regulate the activities and expression of these enzymes will provide new insights into potentially controlling or preventing these disease conditions.