FR 901379 is a pneumocandin belonging to the echinocandin class of cyclic lipopeptides produced by Coleophoma empetri F-11899, discovered as antifungals and patented in 1991 by Ueda and colleagues. FR 901379 inhibits the synthesis of 1,3-β-D-glucan in the fungal cell wall. The sulfonic acid confers water solubility, a limitation with other echinocandins. Unfortunately, FR 901379 was also haemolytic, this limitation being overcome by selective hydrolysis using a cyclic lipopeptide acylase to yield FR 179642, the starting material for production of the commercial antifungal, micafungin.