Butyrolactone I

White to off-white solid. Soluble in DMSO, methanol, ethanol or acetone. Isolated from Aspergillus terreus. Cell permeable, potent and selective cyclin-dependent kinase CDK-1 (CDC2), -2 and -5 inhibitor. Apoptosis inducer. Antitumor agent. Inhibits cell cycle progression at the G1/S and G2/M transitions. Shown to prevent the phosphorylation of retinoblastoma protein and H1 histone. Important probe for understanding the cellular roles of CDKs. Inhibitor of alpha-glucosidases. Maturation inhibitor of sheep oocytes.