Saturday, 9 March 2013

Pore Protein and Carrier Protein

Pore Protein or Channel
When a channel is opened with a conformational switch, it is open to both environment simultaneously (extracellular and intracellular); channels are either in open state or closed state.

Pores are continuously open to these both environment, because they do not undergo conformational changes They are always open.

Carrier Protein

Pathway in a carrier protein is not open smiltaneously to the both environment. Either its inner gate is open, or outer gate is open, or both gates are closed. 

Carrier has binding sites, but porins and channel proteins have not.

When a channel is opened, thousands to millions of ions can pass through the membrane in one time, but only one or a small amount of molecules can pass through a carrier molecule.