Coenzyme Q10 be measured in blood plasma, these measurements reflect dietary intake rather than tissue status. Currently, most clinical centers measure CoQ levels in cultured skin fibroblasts, muscle biopsies, and blood mononuclear cells. Culture fibroblasts can be used also to evaluate the rate of endogenous CoQ biosynthesis, by measuring the uptake of C-labelled "p"-hydroxybenzoate. CoQ shares a biosynthetic pathway with cholesterol. The synthesis of an intermediary precursor of CoQ, mevalonate, is inhibited by some beta blockers, blood pressure-lowering medication, and statins, a class of cholesterol-lowering drugs. Statins can reduce serum levels of CoQ by up to 40%. CoQ is not approved by
Discovery and development of statins that the statins exploit and is used to accommodate their hydrophobic moieties. The specificity and the tight binding of statins is due to orientation and bonding interactions that form between the statin and the HMGR enzyme. Polar interactions are formed between the HMG-moiety and residues that are located in the cis loop of the enzyme. These polar interactions are between Ser, Asp, Lys and Lys (Figure 4). The terminal carboxylate of the HMG moiety forms a salt bridge with the cationic Lys of the enzyme. In addition to the polar interaction, Lys participates in a hydrogen bonding network with Glu,