Elastase, Neutrophil, Human, Affinity Purified

The primary role of neutrophils is to destroy any foreign particles, either by phagocytosis or by release of bacteriostatic agents. Neutrophils contain high concentrations of the serine proteinases neutrophil elastase that is stored in intracellular vacuoles termed the azurophilic granules. This proteinase is a major protein constituent of neutrophils, comprising around 1-3pg per neutrophil. Their primary role is to digest any pathogens that the neutrophil has phagocytosed. , Purulent human sputum is fractionated with sodium chloride and treated with DNase to release DNA-bound proteins. The elastase is purified by affinity chromatography on Agarose-DAPSA-Elastin and separated from cathepsins by ion exchange chromatography. The elastase is further purified by affinity chromatography on agarose-alanyl-alanyl-alanine. The elastase is free of cathepsin G activity when assayed with Suc-AI-AI-Pro-Phe-pNA. Unit Definition: One unit will hydrolyze 1umole of substrate per minute at pH 7.5 and 25°C. Diluents and Stability: 1. 1mg/ml in 0.05M NaOAc pH 5 containing 0.1M NaCI. Stable at least 7 days at 5°C, , 2. 10mg/ml in 50% glycerol 50%, 0.02M NaOAc pH 5. Stable at least 60 days at -20°C with 20 cycles between -20°C and 5°C. 3. May be dissolved at 10mg/ml in 2mM HoAc and re-lyophilized in smaller quantities. Stability is better in acidic (pH 5) than basic buffers. Inactivation may occur at pH 8 due to autolysis and/or proteolysis by trypsin such as bovine pancreatic trypsin. Storage and Stability: Aliquot to avoid repeated freezing and thawing. Store at -70°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.