Apolipoprotein C1
Encyclopedia
Apolipoprotein C-I is a protein component of lipoproteins
that in humans is encoded by the APOC1 gene
.
family. This gene is expressed primarily in the liver, and it is activated when monocytes differentiate into macrophages. A pseudogene
of this gene is located 4 kb downstream in the same orientation, on the same chromosome. This gene is mapped to chromosome 19, where it resides within an apolipoprotein gene cluster. Alternatively spliced transcript variants have been found for this gene, but the biological validity of some variants has not been determined.
Apolipoprotein C1 has a length of 57 amino acid
s normally found in plasma and responsible for the activation of esterified lechitin cholesterol with an important role in the exchange of esterified cholesterol between lipoproteins and in removal of cholesterol from tissues. Its main function is inhibition of CETP, probably by altering the electric charge
of HDL
molecules.
During fasting (like other apolipoprotein
C), it is found primarily within HDL
, while after a meal it is found on the surface of other lipoproteins. When proteins rich in triglycerides like chylomicrons and VLDL are broken down, this apoprotein is transferred again to HDL. It is one of the most positively charged protein
s in the human body.
Lipoprotein
A lipoprotein is a biochemical assembly that contains both proteins and lipids water-bound to the proteins. Many enzymes, transporters, structural proteins, antigens, adhesins, and toxins are lipoproteins...
that in humans is encoded by the APOC1 gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
.
Function
The protein encoded by this gene is a member of the apolipoprotein CApolipoprotein 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 apolipoproteins are mainly associated with HDL...
family. This gene is expressed primarily in the liver, and it is activated when monocytes differentiate into macrophages. A pseudogene
Pseudogene
Pseudogenes are dysfunctional relatives of known genes that have lost their protein-coding ability or are otherwise no longer expressed in the cell...
of this gene is located 4 kb downstream in the same orientation, on the same chromosome. This gene is mapped to chromosome 19, where it resides within an apolipoprotein gene cluster. Alternatively spliced transcript variants have been found for this gene, but the biological validity of some variants has not been determined.
Apolipoprotein C1 has a length of 57 amino acid
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...
s normally found in plasma and responsible for the activation of esterified lechitin cholesterol with an important role in the exchange of esterified cholesterol between lipoproteins and in removal of cholesterol from tissues. Its main function is inhibition of CETP, probably by altering the electric charge
Electric charge
Electric charge is a physical property of matter that causes it to experience a force when near other electrically charged matter. Electric charge comes in two types, called positive and negative. Two positively charged substances, or objects, experience a mutual repulsive force, as do two...
of HDL
High density lipoprotein
High-density lipoprotein is one of the five major groups of lipoproteins, which, in order of sizes, largest to smallest, are chylomicrons, VLDL, IDL, LDL, and HDL, which enable lipids like cholesterol and triglycerides to be transported within the water-based bloodstream...
molecules.
During fasting (like other apolipoprotein
Apolipoprotein
Apolipoproteins are proteins that bind lipids to form lipoproteins and transport the lipids through the lymphatic and circulatory systems....
C), it is found primarily within HDL
HDL
HDL may refer to one of the following:* Hardware description language* High-density lipoprotein, so-called "good cholesterol".* Hong Kong Disneyland, in China.* Les Hurlements d'Léo, an alternative rock band from France.* GE HDL diesel engine...
, while after a meal it is found on the surface of other lipoproteins. When proteins rich in triglycerides like chylomicrons and VLDL are broken down, this apoprotein is transferred again to HDL. It is one of the most positively charged protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
s in the human body.