Apolipoproteins: the apoproteins in lipoproteins


In a wide sense, apoprotein is the term applied to the proteinic part (the one formed by amino acids) of conjugate proteins.


In a more narrow sense, and the one usually used in medical practice, apoprotein is the proteic part of a lipoprotein. From the technical point of view, it is more appropriate to call them “apolipoproteins”  


A common “motif” in the structure of apolipoproteins is the presence of amphipatic helixes that allow the interaction with the aqueous environment that surrounds the lipoprotein, and with the lipid interface of the lipoprotein.


In general, the apolipoproteins, besides contributing to the solubility of the lipoproteins as a whole, act as ligands for cellular receptors and as cofactors of enzymes related to the lipoprotein metabolism.


Apolipoproteins have been classified in families according to the size, distribution in lipoproteins and other characteristics.


The following table shows some important apolipoproteins, whose functions are known:



Molecular Weight

Important Features

Apo A-1

29 000

Main protein in HDL; activates LCAT

Apo B-100

513 000

Main protein in LDL; it binds to LDL receptor

Apo C-II

8 800

Important in the composition of Chylomicrons and VLDL; activates Lipoprotein Lipase.

Apo E

34 000

Important in Chylomicrons, VLDL and IDL, allowing the binding of these lipoproteins to the hepatocytes.



More information about Apoproteins:




 Related Posts:


Structure and Classification of Lipoproteins


 Metabolism of VLDL and Formation of IDL



Metabolism of Chylomicrons





4 thoughts on “Apolipoproteins: the apoproteins in lipoproteins

  1. Pingback: Some questions about Lipoproteins « The Biochemistry Questions Site

  2. Pingback: Metabolism of Very Low Density Lipoproteins (VLDL) and formation of Intermediate Density Lipoproteins (IDL) « The Biochemistry Questions Site

  3. Pingback: Structure and Classification of Lipoproteins « The Biochemistry Questions Site

  4. Pingback: Metabolism of chylomicrons « The Biochemistry Questions Site

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s