Apolipoproteins are proteins that bind lipids (oil-soluble substances such as fat and cholesterol) to form lipoproteins. They transport lipids (and fat soluble vitamins) in blood, cerebrospinal fluid and lymph. The lipid components of lipoproteins are insoluble in water. Apolipoproteins are proteins that transport lipids by binding to them. They also can act as enzyme cofactors and cell-surface receptor ligands. Without proper function of apolipoproteins in the body, a variety of disorders would appear. Most apolipoproteins are made in the liver and intestine, but a small amount of apoB can be made in heart tissue and apoE is made by macrophages. All tissues can degrade apolipoproteins, but most of them are degraded in the liver. Apolipoproteins are proteins that bind lipids (oil-soluble substances such as fat and cholesterol) to form lipoproteins. They transport lipids (and fat soluble vitamins) in blood, cerebrospinal fluid and lymph. The lipid components of lipoproteins are insoluble in water.