Channel proteins; these are one of the two classes of membrane transport proteins. These proteins span the entire membrane, they are transmembranal, water-filled pores that allow specific water-soluble ions to pass. They only allow specific solutes to passively traverse lipid bilayers through an aqueous pore due to the specific size of the ion selectivity filter; the narrowest part of the channel protein only allows specifically charged and sized molecules to pass through. For example the potassium leak channels will only allow potassium to travel through them. Most solutes that pass through channel proteins have a specified molecular weight and charge and are inorganic ions. The concentration and electrical gradients of charged ions determines the direction of flow of the ions and also the rate through the membrane; they move from an area of high to low concentration in processes known as either passive transport or facilitated diffusion. The movement of ions through transporters, the other class of membrane transport proteins, is mediated in contrast to channel proteins either actively or passively .
- ↑ BiologyWise. A Face-off between carrier proteins vs. channel proteins. 2017. [cited 18/11/18]; Available from https://biologywise.com/carrier-proteins-vs-channel-proteins
- ↑ (Molecular Biology Of The Cell, Alberts, et al., 2008, 653)