| Description : |
Defensins (alpha and beta) are cationic peptides with antimicrobial activity against Gram-negative and Gram-positive bacteria, fungi, and enveloped viruses. They are 2-6 kDa proteins and take important roles in innate immune system. On the basis of their size and pattern of disulfide bonding, mammalian defensins are classified into alpha, beta and theta categories. β-Defensins contain a six-cysteine motif that forms three intra-molecular disulfide bonds. Four human β-defensins have been identified and they are expressed on some leukocytes and at epithelial surfaces. Because β-defensins is cationic peptides, they can therefore interact with the membrane of invading microbes, which are negative due to lipopolysaccharides (LPS) and lipoteichoic acid (LTA) found in the cell membrane. Especially, they have higher affinity to the binding site compared to Ca2+ and Mg2+ ions. Furthermore, they can affect the stability of the membrane. |
| Source : |
E.coli |
| Species : |
Human |
| Form : |
Lyophilized from a 0.2μm filtered concentrated solution in 20 mM PB, pH 7.4, 130 mM NaCl. |
| Bio-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. |
| Molecular Mass : |
Approximately 5.2 kDa, a single non-glycosylated polypeptide chain containing 45 amino acids. |
| Protein length : |
45 |
| AA Sequence : |
GIINTLQKYYCRVRGGRCAVLSCLPKEEQIGKCSTRGRKCCRRKK |
| Endotoxin : |
Less than 1 EU/µg of rHuBD-3 as determined by LAL method. |
| Purity : |
>98% by SDS-PAGE and HPLC analysis. |
| Storage : |
Use a manual defrost freezer and avoid repeated freeze-thaw cycles. 12 months from date of receipt, -20 to -70 centigrade as supplied. 1 month, 2 to 8 centigrade under sterile conditions after reconstitution. 3 months, -20 to -70 centigrade under sterile conditions after reconstitution. |
| Reconstitution : |
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 ≤-20 centigrade. Further dilutions should be made in appropriate buffered solutions. |
| Publication : |
Antimicrobial Peptide Resistance Mechanism Contributes to Staphylococcus aureus Infection (2018)
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