Discovery and development of statins as they directly compete with the endogenous substrate for the active site cavity of HMGR. Statins are also noncompetitive with the cosubstrate NADPH (nicotinamide adenine dinucleotide phosphate). By blocking the HMGR enzyme they inhibit the synthesis of cholesterol via the mevalonate pathway. The end result is lower LDL (Low Density Lipoprotein), TG (Triglycerides) and total cholesterol levels as well as increased HDL (High Density Lipoprotein) levels in serum). The ideal statin should have the following properties: One of the main design objectives of statin design is the selective inhibition of HMGR in the liver, as cholesterol synthesis in non-hepatic cells
Discovery and development of statins must be metabolized to their active hydroxy-acid forms in order to inhibit HMGR. Type 2 statins all exist in their active hydroxy-acid forms. Fluvastatin has indole ring structure, while atorvastatin and rosuvastatin have pyrrole and pyrimidine based ring structure respectively. The lipophilic cerivastatin has a pyridine-based ring structure. Studies have shown that statins bind reversibly to the HGMR enzyme. The affinity of statins for HGMR enzyme is in the nanomolar range, while the natural substrate's affinity is in the micromolar range. Studies have shown that statins use the conformational flexibility of the HMGR enzyme that causes a shallow hydrophobic groove