Magainin 2 (Magainin II) is an antimicrobial peptide (AMP) isolated from the skin of the African clawed frog Xenopus laevis. Magainin 2 displays antibiotic activity against numerous gram-negative and gram-positive bacteria. Magainin 2 also is active against protozoa^[1]. Magainin 2 exerts its cytotoxicity effects by preferential interactions with anionic phospholipids abundant in bacterial membranes^[2].

Magainin 2 exhibits bactericidal effects and induces morphological changes in Escherichia coli regarding early apoptosis. Magainin 2 induces the expression of a bacterial protein with affinity for the caspase substrate and effects the expression of RecA as a caspase-like protein^[1]. Magainin 2 kill bacteria by permeabilizing the cell membranes without exhibiting significant toxicity against mammalian cells. The main target of the peptide is considered to be the lipid matrix of the membranes. Application of 10 μg /mL magainin 2 to Paramecium caudatum, a protozoan, in pond water caused an osmotic swelling of the cell and a subsequent cell burst, suggesting that the peptide could perturb membrane functions responsible for osmotic balance^[2]. Magainin 2 permeabilizes bacterial and mammalian membranes in significantly different ways. The peptide forms pores with a diameter of about 2.8 nm (less than 6.6 nm) in B. megaterium, and translocates into the cytosol. In contrast, the peptide significantly perturbes the membrane of CHO-K1 cells, permitting the entry of a large molecule (larger than 23 nm) into the cytosol, accompanied by membrane budding and lipid flip-flop, mainly accumulating in mitochondria and nuclei^[3].

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

2466.90

C₁₁₄H₁₈₀N₃₀O₂₉S

108433-95-0

Gly-Ile-Gly-Lys-Phe-Leu-His-Ser-Ala-Lys-Lys-Phe-Gly-Lys-Ala-Phe-Val-Gly-Glu-Ile-Met-Asn-Ser

GIGKFLHSAKKFGKAFVGEIMNS

蛙皮素 2

Room temperature in continental US; may vary elsewhere.

Protect from light

*In solvent : -80deg;C, 6 months; -20deg;C, 1 month (protect from light)

• [1]. M Zasloff, et al. Magainins, a class of antimicrobial peptides from Xenopus skin: isolation, characterization of two active forms, and partial cDNA sequence of a precursor. Proc Natl Acad Sci U S A. 1987 Aug;84(15):5449-53.

  [2]. K Matsuzaki, et al. Magainins as paradigm for the mode of action of pore forming polypeptides. Biochim Biophys Acta. 1998 Nov 10;1376(3):391-400.

Escherichia coli cells are incubated with magainin 2 (50 μg /mL). The cultures are acquired after incubation for 0, 2, 4, 6, and 8 h, respectively, and spread onto LB agar plates, and then the colony-forming units are counted after incubation for 24 h at 37°C. The percentage survival is determined relative to the control treatment^[1].

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

• [1]. M Zasloff, et al. Magainins, a class of antimicrobial peptides from Xenopus skin: isolation, characterization of two active forms, and partial cDNA sequence of a precursor. Proc Natl Acad Sci U S A. 1987 Aug;84(15):5449-53.

  [2]. K Matsuzaki, et al. Magainins as paradigm for the mode of action of pore forming polypeptides. Biochim Biophys Acta. 1998 Nov 10;1376(3):391-400.