Integral monotopic proteins are permanently attached to the
cell membrane
The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of all cells from the outside environment ( ...
from one side, and are a type of
integral membrane protein
An integral, or intrinsic, membrane protein (IMP) is a type of membrane protein that is permanently attached to the biological membrane. All ''transmembrane proteins'' are IMPs, but not all IMPs are transmembrane proteins. IMPs comprise a signi ...
(IMP).
Three-dimensional structures of the following integral monotopic proteins have been determined:
*prostaglandin H2 syntheses 1 and 2 (
cyclooxygenase
Cyclooxygenase (COX), officially known as prostaglandin-endoperoxide synthase (PTGS), is an enzyme (specifically, a family of isozymes, ) that is responsible for formation of prostanoids, including thromboxane and prostaglandins such as pr ...
s)
*
lanosterol synthase
Lanosterol synthase () is an oxidosqualene cyclase (OSC) enzyme that converts (S)-2,3-oxidosqualene to a protosterol cation and finally to lanosterol. Lanosterol is a key four-ringed intermediate in cholesterol biosynthesis. In humans, lanoster ...
and squalene-hopene cyclase
*microsomal
prostaglandin E synthase
Prostaglandin E synthase (, or PGE synthase) is an enzyme involved in eicosanoid and glutathione metabolism, a member of MAPEG family. It generates prostaglandin E (PGE) from prostaglandin H2.
The synthase generating PGE2 is a membrane-associat ...
*
carnitine O-palmitoyltransferase 2
*
Phosphoglycosyl transferase C
There are also structures of integral monotopic ''domains'' of transmembrane proteins:
*
monoamine oxidases A and B
*
fatty acid amide hydrolase
Fatty acid amide hydrolase or FAAH (, oleamide hydrolase, anandamide amidohydrolase) is a member of the serine hydrolase family of enzymes. It was first shown to break down anandamide in 1993. In humans, it is encoded by the gene ''FAAH''.;
Fun ...
*mammalian
cytochrome P450 oxidase
Cytochromes P450 (CYPs) are a superfamily of enzymes containing heme as a cofactor that functions as monooxygenases. In mammals, these proteins oxidize steroids, fatty acids, and xenobiotics, and are important for the clearance of various compo ...
s
*
corticosteroid 11-beta-dehydrogenases
References
{{DEFAULTSORT:Integral Monotopic Protein
Integral membrane proteins