Arginine

About: Arginine is a research topic. Over the lifetime, 16677 publications have been published within this topic receiving 579791 citations. The topic is also known as: L-Arg & (2S)-2-amino-5-guanidinopentanoic acid.

Cellular and molecular mechanisms of endothelial cell dysfunction.

Abstract: repeated observation that it is altered by a variety of pathophysiological conditions. Such alterations of NO production and/or bioavailability have been shown to occur both in experimental animal models and in human subjects, in the setting of such diverse disorders as hypertension, hypercholesterolemia, aging, cigarette smoking, diabetes, and heart failure (1). The mechanisms underlying the alteration of this important function of the endothelium are varied and likely multifactorial. During the past several years an enormous amount of research has been devoted to understanding these abnormalities, which has led to new insights into regulation of vascular tone, redox state, inflammation, growth, and the prothrombotic/antithrombotic properties of the vessel wall. This Perspective will highlight some of these important new observations, as they relate to the pathology of the endothelial cell L -arginine/NO synthase (NOS) system. In addition, future directions of research that may be particularly informative will be indicated. Alterations of the substrate for the NOS enzyme The substrate for NOS is the basic amino acid L -arginine (with a K m of approximately 5 m M, reference 2). L -Arginine is syn

Arginine metabolism and nutrition in growth, health and disease

Abstract: l-Arginine (Arg) is synthesised from glutamine, glutamate, and proline via the intestinal-renal axis in humans and most other mammals (including pigs, sheep and rats). Arg degradation occurs via multiple pathways that are initiated by arginase, nitric-oxide synthase, Arg:glycine amidinotransferase, and Arg decarboxylase. These pathways produce nitric oxide, polyamines, proline, glutamate, creatine, and agmatine with each having enormous biological importance. Arg is also required for the detoxification of ammonia, which is an extremely toxic substance for the central nervous system. There is compelling evidence that Arg regulates interorgan metabolism of energy substrates and the function of multiple organs. The results of both experimental and clinical studies indicate that Arg is a nutritionally essential amino acid (AA) for spermatogenesis, embryonic survival, fetal and neonatal growth, as well as maintenance of vascular tone and hemodynamics. Moreover, a growing body of evidence clearly indicates that dietary supplementation or intravenous administration of Arg is beneficial in improving reproductive, cardiovascular, pulmonary, renal, gastrointestinal, liver and immune functions, as well as facilitating wound healing, enhancing insulin sensitivity, and maintaining tissue integrity. Additionally, Arg or l-citrulline may provide novel and effective therapies for obesity, diabetes, and the metabolic syndrome. The effect of Arg in treating many developmental and health problems is unique among AAs, and offers great promise for improved health and wellbeing of humans and animals.

Role of a p53 polymorphism in the development of human papillomavirus-associated cancer.

Abstract: The E6 oncoprotein derived from tumour-associated human papillomaviruses (HPVs) binds to and induces the degradation of the cellular tumour-suppressor protein p53 A common polymorphism that occurs in the p53 amino-acid sequence results in the presence of either a proline or an arginine at position 72 The effect of this polymorphism on the susceptibility of p53 to E6-mediated degradation has been investigated and the arginine form of p53 was found to be significantly more susceptible than the proline form Moreover, allelic analysis of patients with HPV-associated tumours revealed a striking overrepresentation of homozygous arginine-72 p53 compared with the normal population, which indicated that individuals homozygous for arginine 72 are about seven times more susceptible to HPV-associated tumorigenesis than heterozygotes The arginine-encoding allele therefore represents a significant risk factor in the development of HPV-associated cancers

L-arginine is required for expression of the activated macrophage effector mechanism causing selective metabolic inhibition in target cells.

Abstract: L-Arginine is required for expression of the activated macrophage cytotoxic effector mechanism that causes inhibition of mitochondrial respiration, aconitase activity, and DNA synthesis in tumor target cells. This effector mechanism is active in the presence of L-arginine even when the cocultivation medium lacks all other amino acids and serum. Cytotoxic activated macrophage-induced inhibition of mitochondrial respiration in target cells is proportional to the concentration of L-arginine in the medium. L-Arginine must be present during the cocultivation period. Pretreatment of cytotoxic activated macrophages with L-arginine or posttreatment of the target cells after cocultivation is not effective. D-Arginine does not substitute for L-arginine and at high concentrations is a competitive inhibitor of the L-arginine-dependent effector mechanism. Other analogues that could not replace L-arginine include agmatine, argininic acid, arginine hydroxamate, and tosyl-L-arginine methyl ester. L-homoarginine, however, can effectively substitute for L-arginine. NG-monomethyl-L-arginine is a potent competitive inhibitor of this effector mechanism. High concentrations of lipopolysaccharide do not reverse inhibition of the L-arginine-dependent effector mechanism by NG-monomethyl-L-arginine. However, inhibition of the effector mechanism by NG-monomethyl-L-arginine can be overridden by increasing the concentration of L-arginine in the culture medium. We compared NGNG-dimethyl-L-arginine and NGN1G-dimethyl-L-arginine with NG-monomethyl-L-arginine as inhibitors of the L-arginine-dependent effector mechanism. The results show that the inhibitory effect of these guanidino methylated derivatives of L-arginine is highly determined by structure. Guanidine is a weak competitive inhibitor of the L-arginine-dependent effector mechanism. The requirement for L-arginine does not appear to be for protein synthesis, creatine biosynthesis, polyamine biosynthesis, or ADP ribosylation reactions. Bacterial lipopolysaccharide is effective as a second signal only when the cocultivation medium contains L-arginine, and this strict L-arginine dependency is not overridden by increasing the concentration of lipopolysaccharide. Bovine liver arginase, by competing for L-arginine in the cocultivation medium, inhibits the L-arginine-dependent activated macrophage cytotoxic effector mechanism.