Absolute configuration and protein tyrosine phosphatase 1B inhibitory activity of xanthoepocin, a dimeric naphtopyrone from Penicillium sp. IQ-429.

Protein tyrosine phosphatase 1B (PTP1B) is an active target for developing drugs to treat type II diabetes, obesity, and cancer. However, in the past, research programs targeting this enzyme focused on discovering inhibitors of truncated models (hPTP1B, hPTP1B, or hPTP1B), losing valuable information about the ligands' mechanism of inhibition and selectivity. Nevertheless, finding an allosteric site in hPTP1B, and the full-length (hPTP1B) protein expression, have shifted the strategies to discover new PTP1B inhibitors.