cholesterol

Cholesterol is a chemical compound that is naturally produced by the body which is a combination of lipid (fat) and steroid. Fat is one of the energy sources that provide the greatest calories after carbohydrate etc, but it is also one component of fat nutrients needed by the body. cholesterol must be transported to bind to proteins that form compounds called lipoproteins. One of the elements that exist in our daily diet is fat. Fat is an energy-rich substance, serves as the primary energy source for the body's metabolic processes. Fat obtained through food or formed in the body, especially the liver and can be stored in fat cells or adipose tissue for future reference. Fat cells also protects the body from the cold, and help to protect the body in many ways. Fat is an essential component of cell membranes, nerve cells that wrap selulubung nerve cells and bile. In addition to fat, there are also other lipid classes that are not related to fatty acids but are still classed as fat because it has properties similar to the actual fat. The same substance is known as lipomimetic compoud, ie components that resemble fat. For example, cholesterol. Cholesterol is a natural substance with physical properties such as fat but have a formula like steroida (Tjay, 2002). Cholesterol is present in tissues and plasma lipoproteins, which can be in the form of free cholesterol or combined with long-chain fatty acids as an ester kolesteril. This element is synthesized in many tissues from acetyl-CoA and eventually expelled from the body in the bile as cholesterol or bile salts. Cholesterol is the precursor of all other steroid compounds within the body, eg, corticosteroids, sex hormones, bile acids and vitamin D (Murray, 2003).

Cholesterol biosynthesis can be divided into five stages as follows:
1. Mevalonic, which is a six-carbon compound, synthesized dariasetil- CoA.
2. Isoprenoid units formed from mevalonic to remove CO2.
3. Six units held isoprenoid condensation to form skualen.
4. Skualen undergo cyclization to produce the parent steroid compound, namely lanosterol.
5. Cholesterol is formed from lanosterol after going through a few more stages Furthermore, including removing three methyl groups (Murray, 2003).