ApoC-II is a protein that plays a crucial role in lipid metabolism, particularly in the transport and breakdown of fats in the bloodstream. It is primarily found in lipoproteins, which are complexes that carry lipids like triglycerides and cholesterol. ApoC-II activates an enzyme called lipoprotein lipase, which helps to hydrolyze triglycerides into free fatty acids for energy use by tissues. Deficiencies or mutations in the ApoC-II gene can lead to disorders related to lipid metabolism, such as hyperlipidemia, where there are elevated levels of lipids in the blood. This can increase the risk of cardiovascular diseases, highlighting the importance of ApoC-II in maintaining healthy lipid levels and overall metabolic health.