Disease relevance of Arg2

• Reduction of arginase I in BDL livers may be responsible for the lowering of arginine levels in the plasma, while induction of arginase II could be important in regulating NO synthesis as well as other important mechanisms involved in liver cirrhosis [1].
• These data demonstrate loss of constitutive expression of arginase II in rat lung as iNOS is upregulated by the response to sepsis [2].

High impact information on Arg2

• The results substantiate the hypothesis that intramitochondrial arginase, presumably the arginase-II isozyme, may play an important role in the regulation of hepatic ureagenesis by furnishing ornithine for net synthesis of N-acetylglutamate, citrulline, and aspartate [3].
• Component I has the amino acid composition Lys6, His, Arg2, Cys3, Asp5, Asn2, Thr3, Ser4, Glu13, Gln3, Pro3, Gly2, Ala6, Val9, Met4, Ile4, Leu8, Tyr6, Phe3, Trp, with serine and asparagine as NH2(-) and COOH-terminal amino acids, respectively [4].
• Ornithine aminotransferase (OAT) and AII were localized using specific antibodies [5].
• Because OAT and AII proteins overlapped in PST mitochondria, L-arginine-derived ornithine may be preferentially converted to L-glutamate, as proven by ornithine oxidation [5].
• OAT and AII were colocalized within PST mitochondria [5].

Biological context of Arg2

• It is concluded that, besides the protonated N-terminal amino group, the guanidino group of the Arg2 side-chain is essential for the manifestation of angiotensin tachyphylaxis in the guinea-pig ileum [6].
• The amino acid sequence, Arg-4-X-3-Lys/Arg-2-Arg-1 decreases X+1, is thought to be a consensus processing site for a constitutive secretory pathway in non-endocrine cells [7].

Anatomical context of Arg2

• There was no regional variation in arginase I or arginase II protein expression across the sub-regions of the hippocampus [8].
• Arginase II protein was localized in some hepatocytes and hyperplastic bile ductular epithelial cells of cirrhotic livers but not in control livers [1].
• In contrast, arginase II mRNA and protein in the small intestine are not detectable at birth, appear at 3 weeks of age, the weaning period, and their levels increase up to 8 weeks [9].
• Immunohistochemical analysis of arginase II, OAT, and OCT in the jejunum revealed their co-localization in absorptive epithelial cells [9].
• Arginase II mRNA and protein are abundant in the intestine (most abundant in the jejunum and less abundant in the ileum, duodenum, and colon) and kidney of the rat [9].

Associations of Arg2 with chemical compounds

• In the kidney, L-ornithine is reabsorbed along the proximal convoluted tubule (PCT), transported by basolateral carriers, and produced by arginase II (AII) [5].
• L-arginine uptake, the citrulline-NO cycle and arginase II in the rat brain: an in situ hybridization study [10].
• Arginase II is elevated in response to a combination of bacterial lipopolysaccharide, dibutyryl cAMP, and dexamethasone in the kidney, but is not affected by these treatments in the small intestine [9].
• Arginase, which catalyzes the conversion of arginine to urea and ornithine, and consists of a liver-type (arginase I) and a non-hepatic type (arginase II) [9].
• The co-localization of arginase II and the three ornithine-utilizing enzymes in the small intestine suggests that the enzyme is involved in the synthesis of proline, polyamines, and/or citrulline in this tissue [9].

Regulatory relationships of Arg2

• Both, LPS and IFN-gamma enhanced the levels of arginase II mRNA and protein, effects also inhibited by dexamethasone [11].

Other interactions of Arg2

• There were no significant differences in nNOS or arginase II expression in the ipsilateral or contralateral VNC at either 10 h or 2 weeks post-UVD [12].
• To examine the expression of endothelial nitric oxide synthase (eNOS), iNOS, and arginase II protein, and mRNA in the corpus cavernosum, immunoblot analysis, and reverse transcriptase-polymerase chain reaction were performed [13].
• Only the substitution of Arg2 reduced affinity to the AT2 receptor considerably (92-fold when compared with Ang II) [14].
• Furthermore, arginase II protein expression as well as immunohistochemical localization of nitrotyrosine was significantly higher in the TGF-beta1-injected corpora cavernosa [13].
• The findings point to a role for vasopressin in the coordinate regulation of several determinants of nitric oxide levels (NOS2, arginase II, NADPH oxidase) and of proteins potentially involved in vasopressin escape (adenylyl cyclase VI and G protein-coupled receptor kinase 4) [15].

Analytical, diagnostic and therapeutic context of Arg2

• Aortic arginase I and arginase II expression as well as arginase activity were evaluated by western blotting and the spectrophotometric method, respectively [16].
• In addition, the expression of arginase II and arginase I mRNA was attenuated by 30 minutes and one hour of reperfusion, and returned to baseline values after 24 hours of reperfusion [17].
• Using RT-PCR mRNA for arginase I was clearly detectable with 30 PCR cycles, whereas mRNA for arginase II was hardly detectable with 35 PCR cycles [18].
• Immunoprecipitation experiments revealed the constitutive presence of arginase-I in both unactivated and LPS-activated cells and arginase-II induction by LPS [19].
• Immunocytochemistry demonstrated that arginase II was homogeneously expressed in IMCD [20].

References