[{"from": "human", "value": "Please give me some details about this molecule. [C][C][C][Branch1][C][C][Branch1][C][C][C][=Branch1][C][=O][O][C@H1][C][C@H1][Branch2][Ring1][P][C][=C][C@H1][Ring1][=Branch1][C@H1][Branch1][=Branch2][C@H1][Branch1][Branch1][C][=C][Ring1][=Branch1][C][C][C][C@@H1][C][C@H1][Branch1][=Branch2][C][C][=Branch1][C][=O][O][Ring1][#Branch1][O][C]"}, {"from": "gpt", "value": "The molecule is a lipid-lowering agent derived synthetically from a fermentation product of the fungus Aspergillus terreus.  Hydrolyzed in vivo to an active metabolite, simvastatin competitively inhibits hepatic hydroxymethyl-glutaryl coenzyme A (HMG-CoA) reductase, the enzyme which catalyzes the conversion of HMG-CoA to mevalonate, a key step in cholesterol synthesis.  This agent lowers plasma cholesterol and lipoprotein levels, and modulates immune responses by suppressing MHC II (major histocompatibility complex II) on interferon gamma-stimulated, antigen-presenting cells such as human vascular endothelial cells. (NCI04)"}]