Reveromycin A, a new antibiotic which inhibits the mitogenic activity of epidermal growth factor.

medium (glucose 2%, soybean meal 2.5%, soluble starch 1 %, meat extract 0.1%, dried yeast 0.4% and NaCl 0.2%, adjusted pH 7.0). The fermentation was carried out at 28°C, 350rpm stirring speed and 18 liters/minute aeration rate for 72 hours. The fermentation and the following purification procedure were monitored by the inhibitory activity of [3H]thymidine-uptake into Balb/MK cells stimulated with EGFas described in our previous paper1}. The culture filtrate was adjusted to pH 10 and extracted with the same volume of EtOAc. In alkaline condition, the antibiotic remained in the aqueous layer. The antibiotic was extracted into the organic layer after the pH of the aqueous layer was adjusted at pH 5. The extract was concentrated and purified by a silica gel column (100% MeOH). The active fractions were combined and further purified