Lipitor, a medication commonly prescribed for lowering cholesterol levels, works by inhibiting the production of a specific type of protein that plays a crucial role in the body's cholesterol production process. This protein is known as HMG-CoA reductase [1].

HMG-CoA reductase is an enzyme that facilitates the conversion of HMG-CoA to mevalonate, which is a key step in the production of cholesterol within the body [2]. By inhibiting this enzyme, Lipitor reduces the production of cholesterol, thereby helping to lower the levels of low-density lipoprotein (LDL), or "bad" cholesterol, in the blood [1].

It is important to note that while Lipitor primarily affects the production of proteins linked to cholesterol, it does not directly affect the production of all proteins. Its mechanism of action is specific to HMG-CoA reductase, which is a key enzyme in the cholesterol biosynthesis pathway [2].

In summary, Lipitor inhibits the production of HMG-CoA reductase, an enzyme that plays a critical role in cholesterol production. This inhibition leads to a decrease in cholesterol levels, helping to manage conditions such as high cholesterol and related cardiovascular diseases.

Sources:
[1] Mayo Clinic. (2021). Atorvastatin (Oral Route). Retrieved from <https://www.mayoclinic.org/drugs-supplements/atorvastatin-oral-route/description/drg-20063093>
[2] National Center for Biotechnology Information. (2021). HMG-CoA reductase. Retrieved from <https://www.ncbi.nlm.nih.gov/books/NBK535452/>
[3] DrugPatentWatch. (2021). Lipitor (Atorvastatin) Drug Patent Expiration & Generic Launch Dates. Retrieved from <https://www.drugpatentwatch.com/drugs/lipitor>