Lipid metabolism is the break down or storage of fats for energy. These fats are obtained from food or synthesized by an animal's liver. Lipid metabolism occurs in plants, though the processes differ in some ways compared to animals. Lipogenesis is the process of synthesizing fats. Lipid metabolism often begins with hydrolysis, which occurs when a chemical breaks down as a reaction to coming in contact with water. Since lipids (fats) are hydrophobic, hydrolysis in lipid metabolism occurs in the cytoplasm which ends up creating glycerol and fatty acids. Due to the hydrophobic nature of lipids they require special transport proteins known as lipoproteins, which are hydrophilic. Lipoproteins are categorized by their density levels. The varying densities between the types of lipoproteins are characteristic to what type of fats they transport. Some lipoproteins are synthesized in the liver; others originate elsewhere.
Description source: [Wikipedia](https://en.wikipedia.org/wiki/Lipid_metabolism).
Proteins on this pathway have targeted assays available via the [CPTAC Assay Portal](https://assays.cancer.gov/available_assays?wp_id=WP3965).