PI3 Human, Sf9

PI3 belongs to the WAP-type four-disulfide core (WFDC) domain family. This family is characterized by the presence of a WAP-type four-disulfide core domain, which is essential for the protein’s stability and function . Most members of the WFDC gene family are localized to chromosome 20q12-q13 in two clusters: centromeric and telomeric. PI3 is part of the centromeric cluster .

The human recombinant form of PI3, produced in Sf9 Baculovirus cells, is a single, glycosylated polypeptide chain containing 101 amino acids (23-117 a.a.) and has a molecular mass of approximately 10.7 kDa . This recombinant form is fused to a 6 amino acid His-tag at the C-terminus and is purified using proprietary chromatographic techniques .

PI3 functions as an antimicrobial peptide against Gram-positive and Gram-negative bacteria, as well as fungal pathogens . It is particularly effective in inhibiting neutrophil and pancreatic elastase, which are enzymes that can degrade various proteins in the extracellular matrix, leading to tissue damage . By inhibiting these enzymes, PI3 helps maintain tissue integrity and prevent excessive inflammation and tissue destruction.

The expression of PI3 is upregulated by bacterial lipopolysaccharides and cytokines, indicating its role in the body’s immune response . Additionally, PI3 has been associated with various diseases, including pustular psoriasis and impetigo . Its ability to inhibit elastase makes it a potential therapeutic target for conditions involving excessive tissue proteolysis.

For laboratory research purposes, PI3 should be stored at 4°C if it will be used within 2-4 weeks. For longer storage periods, it is recommended to store the protein frozen at -20°C, with the addition of a carrier protein (0.1% HSA or BSA) to prevent degradation . It is crucial to avoid multiple freeze-thaw cycles to maintain the protein’s stability and functionality .