Some of the transport proteins carry out the diffusion when two molecules are moving through it together. Moving of molecules across the membrane in one direction is called as symport. If the molecules move in the opposite direction, then it is called as antiport. If one molecule is moving in a different direction than the other molecules, then the movement process is called as uniport.
If the molecules are transferred through the membrane across the concentration gradient with the use of energy then the process is called as Active transport. The membrane proteins are involved in carrying out the active transport. The proteins in the membrane play important role in the active transport and passive transport. Pumps are the membrane proteins which make use of energy to transport the substances against the membrane of the cell. These transport proteins or channels will transfer the substances from their low concentration side to their high concentration side.
The rate of transport will be maximum when the transporting proteins are made use of and are saturated. The membrane protein is very much specific towards the substance that is transferred across the membrane which is the characteristic of an enzyme. Certain inhibitors work on these proteins and make them non-functioning by reacting with the side chains of the proteins.