EM-1745

EM-1745 is a synthetic steroidal glycoside designed as a bisubstrate inhibitor targeting 17β-hydroxysteroid dehydrogenase type 1 (17β-HSD1), an enzyme involved in the final step of estradiol biosynthesis. By competitively binding to both the substrate and cofactor sites of 17β-HSD1, EM-1745 effectively inhibits the conversion of estrone (E1) to estradiol (E2), which is significant in estrogen-sensitive diseases such as breast cancer. The compound features an estradiol–adenosine hybrid structure with an eight-carbon linker, providing high affinity and potent inhibition (Ki ≈ 3 nM; IC50 ≈ 4 nM). Its mechanism has been validated by X-ray crystallography, showing strong interactions at both binding sites[2][4][5].