Arginase Liver Type Human ELISA

Research topic

Blood pressure regulation and NO metabolism

Features

The total assay time is less than three hours.

• The kit measures total serum liver-type arginase.
• Quality controls are human serum based. No animal sera are used.
• Serum samples require very careful preparation. The erythrocytes have to be spinned down immediately (within few seconds) after taking blood to avoid hemolysis and contamination of the sample with erythrocyte arginase.

Storage/Shipping

Place the lyophilized Master Standards and Quality Controls at –20 °C after the kit delivery. Store the other kit components at 2–8°C. Under these conditions the kit is stable till the expiry date is over. (See the expiry date indicated on the kit label).

Summary

Arginase [EC 3.5.3.1; L-arginine aminohydrolase] is an enzyme that hydrolyzes Larginine to L-ornithine and urea in the urea cycle. Two forms of arginase exists which are designed as arginase I and arginase II. Liver-type arginase I is expressed primarily in the liver and to some extend in the erythrocytes. Arginase II is expressed in many extrahepatic tissues, such as brain, spinal cord, kidney, small intestine and mammary gland. Although arginase I and arginase II have similar enzyme activities, they have different pI, immunological reactivity and are encoded by different genes. Human arginase I is a 35 kDa protein circulating in blood probably as a homotrimer. Circulating liver-type arginase was clinically used as a liver specific marker which may reflect not only early occurrence of liver injury but also early termination of liver injury. The measurement of liver-type arginase is clinically applicable for monitoring conditions of patients with liver disorders or pre- and postoperative conditions of patients who received partial hepatectomy with quicker normalization in comparison with aminotransferases (ALT and AST). Recently, arginase I gene was found to be one of the most prominent among astma genes. In situ hybridization demonstrated marked staining of arginase I in submucosal inflammatory lesions and arginase activity increased in allergen challenged lungs. Finally, it was found that both arginase I was the most significantly up-regulated protein in the murine spinal cord during experimental autoimmune encephalomyelitis. The results indicated that arginase I played important roles in autoimmune inflammation in the central nervous system.

Assay format

Sandwich ELISA, HRP-labelled antibody

Sample requirements

25 µl/well

Applications

Cerebrospinal fluid, Serum

Calibration Curve

Limit of detection

Analytical Limit of Detection is calculated from the real human arginase liver-type values in wells and is 0.5ng/ml

Limit of quantification

Assay Sensitivity takes the dilution of samples into consideration and is calculated according to the formula: Assay Sensitivity = Analytical Limit of Detection x sample dilution = 0.17ng/ml x 4 = 2.0ng/ml

Intra-assay (Within-Run, n=8)

CV = 5.8 %

Inter-assay (Run-to-Run, n=8)

CV = 8.0 %

Spiking Recovery

87 %

Dilution Linearity

91 %

Cross-Reactivity

Human, Monkey

References to this product

• Silva MA, Mirza DF, Buckels JA, Bramhall SR, Mayer D, Wigmore SJ, Murphy N, Richards DA . Arginine and urea metabolism in the liver graft: A study using microdialysis in human orthotopic liver transplantation. Transplantation . Nov 27;82(10):1304-11 (2006)
• Grasemann H, Schwiertz R, Grasemann C, Vester U, Racke K, Ratjen F . Decreased systemic bioavailability of L-arginine in patients with cystic fibrosis. Respir Res . Jun 9;7:87 (2006)
• Larkin SK, Morris CR, Styles LA, Kuypers FA . Elevated Plasma Arginase Levels in Hemoglobinopathies. Blood . 106 (11) (2005)

References to summary

• Ikemoto M, Tsunekawa S, Awane M, Fukuda Y, Murayama H, Igarashi M, Ngata A, Kasai Y, Totani M: A useful ELISA system for human liver-type arginase, and its utility in diagnosis of liver diseases. Clin Biochem. 34, 455–461 (2001).
• Ikemoto M, Tsunekawa S, Tanaka K, Tanaka A, Yamaoka Y, Ozawa K, Fukuda Y, Moriyasu F, Totani M, Kasai Y, Mori T, Ueda K: Liver-type arginase in serum during and after liver transplantation: a novel index in monitoring conditions of the liver graft and its clinical significance. Clin Chim Acta. 271, 11–23 (1998).
• Zimmermann N, King NE, Laporte J, Yang M, Mishra A, Pope SM, Muntuel EE, Witte DP, Pegg AA, Foster PS, Hamid Q, Rothenberg ME: Dissection of experimental asthma with DNA microarray analysis identifies arginase in asthma pathogenesis. J Clin Invest. 111, 1863–1874 (2003).
• Vercelli D: Arginase: marker, effector, or candidate gene for asthma? J Clin Invest. 111, 1815–1817 (2003).
• Xu L, Hilliard B, Carmody RJ, Tsabry G, Shin H, Christianson DW, Chen YH: Arginase and immune inflammation in the central nervous system. Immunology. 110, 141–148 (2003).
• Roikhel VM, Fokina GI, Khokhlov AI, Sobolev SG, Zavalishin IA, Korolev MB, Pogodina VV: Alterations of arginase activity in scrapie-infected mice and in amyotrophic lateral sclerosis. Acta Virol. 34, 545–553 (1990).
• Ikemoto M, Tabata M, Miyake T, Kono T, Mori M, Totani M, Murachi T: Expression of human liver arginase in Escherichia coli. Purification and properties of the product. Biochem J. 270, 697–703 (1990).
• Lavulo LT, Sossong TM Jr, Brigham-Burke MR, Doyle ML, Cox JD, Christianson DW, Ash DE: Subunit-subunit interactions in trimeric arginase. Generation of active monomers by mutation of a single amino acid. J Biol Chem. 276, 14242–14248 (2001).
• Dillon BJ, Holtsberg FW, Ensor CM, Bomalaski JS, Clark MA: Biochemical characterization of the arginine degrading enzymes arginase and arginine deiminase and their effect on nitric oxide production. Med Sci Monit. 8, :BR248–253 (2002)