Phospholipid translocators
| Phospholipid translocators | ||
|---|---|---|
| Transporter classification | ||
| TCDB | 3.A.3.8 | |
| designation | P-ATPase superfamily | |
| Enzyme classification | ||
| EC, category | 3.6.3.1 , hydrolase | |
| Substrate | Phospholipid (in / out) + ATP + H 2 O | |
| Products | Phospholipid (out / in) + ADP + phosphate | |
| Occurrence | ||
| Parent taxon | Eukaryotes | |
Phospholipid translocators , also known as flippases or phospholipid flippases , are special transport proteins that are dependent on ATP and occur in both the plasma membrane and the membrane of the smooth endoplasmic reticulum and the Golgi apparatus of eukaryotes . 14 human isoforms are known.
Their job is to transport various phospholipids from one side of the membrane to the other. This transport is necessary because the various phospholipids are formed in the cytoplasm. Even growth of the lipid bilayer of the organelles is only achieved if they are also transported to the other side. The lipids with their polar head group have to migrate through the interior of the hydrophobic membrane. This transport takes place through membrane-based transport proteins, the flippases. The process itself is called a flip-flop .
A distinction is made between three different enzyme classes:
- Flippases (P-type ATPase): mainly move aminophospholipids (PE and PS) from the extracellular to the cytosolic layer.
- Floppases ( ABC transporters ): transports phospholipids from the cytosolic to the extracellular layer.
- Scrambladder : transports lipids in both directions independently of ATP until equilibrium is established.
Individual evidence
- ↑ Entry at TCDB
- ↑ ENZYME entry
- ^ David Nelson (biochemist) , Michael Cox : Lehninger Biochemie Springer Verlag , 2011, ISBN 978-3540686378