Lysosomal lipase

Lysosomal lipase is an enzyme that is encoded by the LIPA gene in humans. It is a key component in the metabolism of lipids, specifically in the hydrolysis of triglycerides in the lysosome.

Function

Lysosomal lipase, also known as lysosomal acid lipase (LAL), is responsible for the breakdown of cholesterol esters and triglycerides. It is the only enzyme capable of hydrolyzing cholesteryl esters within the lysosome. The enzyme is active at an acidic pH, which is the environment found within the lysosome.

Structure

The LIPA gene provides instructions for making the lysosomal lipase enzyme. This enzyme is made up of 398 amino acids and has a molecular weight of approximately 46 kDa. The enzyme is synthesized as a preproenzyme, which is then processed into a mature enzyme within the lysosome.

Clinical significance

Mutations in the LIPA gene can lead to a deficiency in lysosomal lipase, resulting in two distinct diseases: Wolman disease and cholesteryl ester storage disease (CESD). Both diseases are characterized by the accumulation of cholesteryl esters and triglycerides in various tissues, leading to organ damage.

Wolman disease is a severe form of lysosomal lipase deficiency that begins in infancy. Symptoms include failure to thrive, enlarged liver and spleen, and adrenal gland dysfunction.

Cholesteryl ester storage disease (CESD) is a milder form of lysosomal lipase deficiency that may not become apparent until later in life. Symptoms can include liver disease, high cholesterol levels, and premature atherosclerosis.

See also

• Lipase
• Lysosome
• Metabolism
• Wolman disease
• Cholesteryl ester storage disease