What is Membrane proteins?

Integral membrane proteins span the bilayer with one or more hydrophobic helices and can only be extracted with detergents; peripheral proteins are bound to one face. By function: transporters (channels, carriers, pumps), receptors that bind a signal outside and act inside, enzymes, anchors linking the cytoskeleton to the extracellular matrix, and recognition proteins bearing the sugars by which cells identify one another. Proteins are half the mass of a typical membrane and nearly all of its function.