Apolipoprotein C-II (Apo-CII, or Apoc-II), or apolipoprotein C2 is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
that in humans is encoded by the
gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
.
The protein encoded by this gene is secreted in plasma where it is a component of
very low density lipoprotein
Very-low-density lipoprotein (VLDL), density relative to extracellular water, is a type of lipoprotein made by the liver. VLDL is one of the five major groups of lipoproteins (chylomicrons, VLDL, intermediate-density lipoprotein, low-density lipo ...
s and
chylomicron
Chylomicrons (from the Greek χυλός, chylos, meaning ''juice'' (of plants or animals), and micron, meaning ''small particle''), also known as ultra low-density lipoproteins (ULDL), are lipoprotein particles that consist of triglycerides (85 ...
s. This protein activates the enzyme
lipoprotein lipase
Lipoprotein lipase (LPL) (EC 3.1.1.34, systematic name triacylglycerol acylhydrolase (lipoprotein-dependent)) is a member of the lipase gene family, which includes pancreatic lipase, hepatic lipase, and endothelial lipase. It is a water-soluble ...
in capillaries,
which hydrolyzes triglycerides and thus provides free
fatty acid
In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, fr ...
s for cells. Mutations in this gene cause
hyperlipoproteinemia type IB, characterized by
xanthoma
A xanthoma (pl. xanthomas or xanthomata) (condition: xanthomatosis) is a deposition of yellowish cholesterol-rich material that can appear anywhere in the body in various disease states. They are cutaneous manifestations of lipidosis in which lip ...
s,
pancreatitis
Pancreatitis is a condition characterized by inflammation of the pancreas. The pancreas is a large organ behind the stomach that produces digestive enzymes and a number of hormones. There are two main types: acute pancreatitis, and chronic pancr ...
, and
hepatosplenomegaly
Hepatosplenomegaly (commonly abbreviated HSM) is the simultaneous enlargement of both the liver (hepatomegaly) and the spleen (splenomegaly). Hepatosplenomegaly can occur as the result of acute viral hepatitis, infectious mononucleosis, and hist ...
, but no increased risk for
atherosclerosis
Atherosclerosis is a pattern of the disease arteriosclerosis in which the wall of the artery develops abnormalities, called lesions. These lesions may lead to narrowing due to the buildup of atheroma, atheromatous plaque. At onset there are usu ...
. Lab tests will show elevated blood levels of triglycerides, cholesterol, and chylomicrons
Interactive pathway map
See also
*
Apolipoprotein C
In the field of molecular biology, apolipoprotein C is a family of four low molecular weight apolipoproteins, designated as C-I, C-II, C-III, and C-IV that are surface components of chylomicrons, VLDL, and HDL. In the fasting state, the C apol ...
References
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
External links
*
{{Lipoproteins
Apolipoproteins