Brevinin-1 and -2, unique antimicrobial peptides from the skin of the frog, Rana brevipoda porsa.

Two unique antimicrobial peptides named brevinin-1 and -2 were isolated from the skin of the frog, Rana brevipoda porsa. Both of the peptides did not have any structural homology with bombinin nor magainin; the frog skin derived-antimicrobial peptides isolated from Bombina and Xenopus, nor even with other known antimicrobial peptides of non-amphibian origin. The minimum inhibitory concentration of brevinin-1 against the growth of St. aureus and E. coli was determined to be 8 micrograms/ml and 34 micrograms/ml while that of brevinin-2 was 8 micrograms/ml and 4 micrograms/ml, respectively, indicating the difference of the two peptides in the antimicrobial selectively on Gram-positive and Gram-negative bacteria.