Purity ≥ 95% by HPLC. Antibiotic LL Z1640-4 is a cis-enol resorcylic acid lactone first reported in 1978 exhibiting both antiviral and antiprotozoan activity. More recently, antibiotic LL Z1640-2 containing the essential cis-enone system that selectively inhibits TAK 1 has gained literature focus. With its inactive cis-enol, Antibiotic LL Z1640-4 is an ideal negative control to help dissect the selectivity of the MAP kinases. Source: Antibiotic LL Z1640-4 Molecular Weight: ~364.4 Solubility: Soluble in ethanol, methanol, DMF or DMSO. Limited water solubility.