Wu G, Morris S M
Departments of Animal Science, Medical Physiology, and Veterinary Anatomy and Public Health, and Faculty of Nutrition, Texas A&M University, College Station, TX 77843, USA.
Biochem J. 1998 Nov 15;336 ( Pt 1)(Pt 1):1-17. doi: 10.1042/bj3360001.
Arginine is one of the most versatile amino acids in animal cells, serving as a precursor for the synthesis not only of proteins but also of nitric oxide, urea, polyamines, proline, glutamate, creatine and agmatine. Of the enzymes that catalyse rate-controlling steps in arginine synthesis and catabolism, argininosuccinate synthase, the two arginase isoenzymes, the three nitric oxide synthase isoenzymes and arginine decarboxylase have been recognized in recent years as key factors in regulating newly identified aspects of arginine metabolism. In particular, changes in the activities of argininosuccinate synthase, the arginases, the inducible isoenzyme of nitric oxide synthase and also cationic amino acid transporters play major roles in determining the metabolic fates of arginine in health and disease, and recent studies have identified complex patterns of interaction among these enzymes. There is growing interest in the potential roles of the arginase isoenzymes as regulators of the synthesis of nitric oxide, polyamines, proline and glutamate. Physiological roles and relationships between the pathways of arginine synthesis and catabolism in vivo are complex and difficult to analyse, owing to compartmentalized expression of various enzymes at both organ (e.g. liver, small intestine and kidney) and subcellular (cytosol and mitochondria) levels, as well as to changes in expression during development and in response to diet, hormones and cytokines. The ongoing development of new cell lines and animal models using cDNA clones and genes for key arginine metabolic enzymes will provide new approaches more clearly elucidating the physiological roles of these enzymes.
精氨酸是动物细胞中用途最为广泛的氨基酸之一，它不仅是蛋白质合成的前体，也是一氧化氮、尿素、多胺、脯氨酸、谷氨酸、肌酸和胍丁胺合成的前体。近年来，在催化精氨酸合成和分解代谢中限速步骤的酶中，精氨琥珀酸合成酶、两种精氨酸酶同工酶、三种一氧化氮合酶同工酶和精氨酸脱羧酶已被公认为调节精氨酸代谢新发现方面的关键因素。特别是，精氨琥珀酸合成酶、精氨酸酶、一氧化氮合酶诱导型同工酶以及阳离子氨基酸转运体活性的变化在决定健康和疾病状态下精氨酸的代谢命运中起主要作用，并且最近的研究已经确定了这些酶之间复杂的相互作用模式。人们对精氨酸酶同工酶作为一氧化氮、多胺、脯氨酸和谷氨酸合成调节剂的潜在作用越来越感兴趣。由于各种酶在器官（如肝脏、小肠和肾脏）和亚细胞（细胞质和线粒体）水平上的分区表达，以及在发育过程中以及对饮食、激素和细胞因子的反应中表达的变化，精氨酸在体内合成和分解代谢途径之间的生理作用和关系是复杂且难以分析的。使用关键精氨酸代谢酶的cDNA克隆和基因不断开发新的细胞系和动物模型，将提供新的方法，更清楚地阐明这些酶的生理作用。
