Defensins (alpha and beta) are cationic peptides with a broad spectrum of antimicrobial activity that comprise an important arm of the innate immune system. The alpha-defensins are distinguished from the beta-defensins by the pairing of their three disulfide bonds. To date, four human beta-defensins have been identified, BD-1, BD-2, BD-3 and BD-4. The beta-defensin proteins are expressed as the C-terminal portion of precursors and are released by proteolytic cleavage of a signal sequence. beta-defensins contain a six-cysteine motif that forms three intra-molecular disulfide bonds. beta-defensins are 3-5 kDa peptides ranging in size from 33-47 amino acid residues. BD-4 is expressed in testis, stomach, uterus, neutrophils, thyroid, lung and kidney. In addition to its direct antimicrobial activities, BD-4 is chemoattractant towards human blood monocytes.
Molecular Weight:
Approximately 6.0 KDa, a single non-glycosylated polypeptide chain containing 50 amino acids.
Source:
Escherichia coli.
Purity:
>98% by SDS-PAGE and HPLC analyses.
Form:
Sterile Filtered White lyophilized (freeze-dried) powder.
Lyophilized from a 0.2m filtered concentrated solution in 20mM PB, pH 7.4, 130mM NaCl.
Application Notes:
We recommend that this vial be briefly centrifuged prior to opening to bring the contents to the bottom. Reconstitute in sterile distilled water or aqueous buffer containing 0.1% BSA to a concentration of 0.1-1.0 mg/mL. Stock solutions should be apportioned into working aliquots and stored at <-20C. Further dilutions should be made in appropriate buffered solutions.
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