| Source: |
Escherichia coli. |
| Molecular Weight: |
Approximately 5.2 kDa, a single non-glycosylated polypeptide chain containing 45 amino acids. |
| AA Sequence: |
GIINTLQKYY CRVRGGRCAV LSCLPKEEQI GKCSTRGRKC CRRKK |
| Purity: |
> 98% by SDS-PAGE and HPLC analyses. |
| Biological Activity: |
Fully biologically active when compared to standard. The ED50 as determined by anti-microbial activity against E. coli. is less than 30 μg/mL, corresponding to a specific activity of > 33.3 IU/mg. |
| Physical Appearance: |
Sterile filtered white lyophilized (freeze-dried) powder. |
| Formulation: |
Lyophilized from a 0.2 µm filtered concentrated solution in 20 mM PB, pH7.4, 130 mM NaCl. |
| Endotoxin: |
Less than 1 EU/µg of rHuBD-3 as determined by LAL method. |
| Reconstitution: |
Centrifuge the vial briefly before opening to ensure that the contents settle at the bottom. Reconstitute the vial with sterile distilled water or an aqueous buffer containing 0.1% BSA to achieve a concentration of 0.1-1.0 mg/mL. Divide the resulting stock solution into working aliquots and store them at or below -20°C. For further dilutions, use appropriate buffered solutions. |
| Stability & Storage: |
Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
12 months from date of receipt, -20 to -70°C as supplied.
1 month, 2 to 8°C under sterile conditions after reconstitution.
3 months, -20 to -70°C under sterile conditions after reconstitution. |
| Synonyms: |
Defensin beta3 |
| Background: |
Defensins, both alpha and beta, are cationic peptides that function as antimicrobials against Gram-negative and Gram-positive bacteria, fungi and enveloped viruses. As 2-6 kDa proteins, defensins play important roles in the innate immune system. Mammalian defensins are categorized into alpha, beta, and theta categories based on their size and disulfide bond pattern. The beta category of defensins, the β-defensins, contain a six-cysteine motif that creates three intra-molecular disulfide bonds. There are four identified human β-defensins, which are expressed on some leukocytes and at epithelial surfaces. As β-defensins are cationic peptides, they interact with the negatively charged membranes of invading microbes due to the presence of lipopolysaccharides (LPS) and lipoteichoic acid (LTA) in the cell membrane. Notably, they exhibit a higher affinity to the binding site than Ca2+ and Mg2+ ions, impacting the membrane's stability. |
