Purity: > 85% by SDS - PAGE. Format: Liquid. In phosphate buffered saline (pH7.4), 10% glycerol.. PI3, also known as elafin or peptidase inhibitor 3, is neutrophil and pancreatic elastase-specific inhibitor of skin. It may prevent elastase-mediated tissue proteolysis. Recombinant human PI3, fused to His-tag at C-terminus, was expressed in insect cell and purified by using conventional chromatography techniques.