We have previously discussed how chemical potential energy in the form of reduced organic molecules can be transduced into the chemical potential energy of ATP. This ATP can be used to drive reductive biosynthesis and movement (from individual cells to whole organisms). ATP has two other significant uses in the cell.
- Active Transport
- Examples of Transport: Metal Ions
- Examples of Transport: Protons
- Examples of Transport: Sugars
- Examples of Other "Transporter" Powered by ATP
Drugs and Diffusion: Part 2
As mentioned earlier, one of the biggest problems in medical drug development is the productions of drugs that can diffuse across the cell membrane.This requires that the drug be sufficiently nonpolar while at the same time being sufficiently polar to have reasonable aqueous solubility, allowing blood transport.Another approach to getting drugs across the membrane is to modify them to bind to transporters whose normal function is to move solutes against a concentration gradient across a lipid bilyaer.The extent of modification of the drug depends on how close the structure of the drug is in comparison to the normal ligand for the transporter. This approach has been used by the biotech company XenoPort, to develop drugs that can be more readily absorbed by the small intestine, which has many active transporters designed to move nutrients into cells.
- Science 320: 528 (2008)
- The xyz of ABC Transporters (require ATP, overexpression lead to resistance to antibiotics, chemotherapy, etc).Science. 293, pg 1782 (2001)
- Bacteriorhodopsin- the movie.Nature.406, pg 569, 645, 649, 653 (2000)
- Toyoshima et al. Structure of sacroplasmic reticulum Ca pump.Nature. 405, pg 633, 647 (2000)
- Luecke, H. et al. Structural Changes in Bacteriorhodopsin During Ion Transport at 2 Angstrom Resolution, Science 286, 255 (1999).