Surfactin is an acidic lipopeptide produced by Bacillus subtilis strains. At high concentrations (above its critical micellar concentration (CMC) of 9 μM) it is a biosurfactant. It is also an antibacterial, antiviral, antitumor agent that lyses erythrocytes and inhibits formation of fibrin clots. At low concentrations (below its CMC) it forms pores in membranes (Carrillo et al., 2003), allowing leakage of carboxyfluorescein from unilamellar vesicles. Its activity is dependent on the lipid composition of the vesicles. It interacts with the phospholipid acyl chains.

Surfactin is a cyclic lactone peptide of 7 aas. The structure is provided in Carrillo et al. (2003). It is made by surfactin synthetase (BAA02523), a 3072 aa, multidomain protein in which each domain catalyzes the addition of a different D- or L-amino acid to the growing chain.

The transport reaction catalyzed by surfactin is:

small molecules (in) small molecules (out)