Arginase exists as two forms designated arginase-I and arginase-II which are encoded by different genes. Although arginase-I and arginase-II have similar enzyme activities, they differ in pI and immunological reactivity. Human arginase-I (liver-type arginase) is a 35 kD protein circulating in blood probably as a homotrimer. Liver-type arginase is most abundant expressed in mammalian liver, but is also found in non-hepatic tissues, for instance red blood cells, lactating mammalian glands, and the kidney. In addition to its involvement in ammonia detoxification via the urea cycle, arginase plays a role in other processes, for instance macrophage-mediated cytotoxicity due to arginase release and inhibition of lymphocyte proliferation in vitro. It shows high activity in growing tissues, wound healing, proliferating lymphocytes and tumors. Furthermore, arginase acts as a modulator of the immune response. Besides this arginase plays a role in allergen challenged lungs, in autoimmune inflammation in the central nervous system and in acute liver injury.
In plasma of healthy individuals arginase-I is present in levels of 1.8 - 30 ng/ml, which increases approximately 10 fold during acute phase responses.- Minimum concentration which can be measured is 0.4 ng/ml human arginase-I.
- Measurable concentration range of 0.4-100 ng/ml.
- Working volume of 100 µl/well.
- The human arginase-I ELISA is a ready-to-use solid-phase enzyme-linked immunosorbent assay based on the sandwich principle with a working time of 3½ hours.
- The efficient format of a plate with twelve disposable 8-well strips allows free choice of batch size for the assay.
- Samples and standards are captured by a solid bound specific antibody.
- Biotinylated tracer antibody will bind to captured human arginase-I.
- Streptavidin-peroxidase conjugate will bind to the biotinylated tracer antibody.
- Streptavidin-peroxidase conjugate will react with the substrate, tetramethylbenzidine (TMB).
- The enzyme reaction is stopped by the addition of citric acid.
- The absorbance at 450 nm is measured with a spectrophotometer. A standard curve is obtained by plotting the absorbance (linear) versus the corresponding concentrations of the arginase-I standards (log).
- The human arginase-I concentration of samples, which are run concurrently with the standards, can be determined from the standard curve.
- Ikemoto, M et al; A useful ELISA system for human liver-type arginase, and its utility in diagnosis of liver diseases. Clin Biochem 2001, 34: 455
- Debats, I et al; Infected chronic wounds show different local and systemic arginine conversion compared with acute wounds. J Surg Res 2006, 134: 205
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Ikemoto, M et al; A useful ELISA system for human liver-type arginase, and its utility in diagnosis of liver diseases. Clin Biochem 2001, 34: 455
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Debats, I et al; Infected chronic wounds show different local and systemic arginine conversion compared with acute wounds. J Surg Res 2006, 134: 205