Question

why is it important for determining the function of a membrane protein to know if it spans the bilayer or appears only on one face of the membrane? provide 3 example proteins and their functions.

Answer 1

1. The transmembrane proteins span across the lipid bilayer and therefore function as channels or active transport molecules to convey other molecules across the membrane .An example of transmembrane protein is cell surface receptors .These function by binding signal molecules in the extracellular space and produce various intracellular signals on the interior of the membrane.Another example of transmembrane proteins is voltage gated ion channels that provides the outlet for the diffusion of the substrate.

Proteins that are present only on one side of the membrane are either associated with lipids or protein moeity of the membrane.Examples of such poteins are enzymes such as cyclooxygenase and carnitine O- palmitoyltansferase.Proteins involved in intracellular signalling are bound to the cytosolic half of the plasma membrane.