<P> In 1997, Jens Christian Skou, a Danish physician received the Nobel Prize in Chemistry for his research regarding the sodium - potassium pump </P> <P> One category of cotransporters that is especially prominent in research regarding diabetes treatment is sodium glucose cotransporters . These transporters were discovered by scientists at that National Health Institute . These scientists had noticed a discrepancy in the absorption of glucose at different points in the kidney tubule of a rat . The gene was then discovered for intestinal glucose transport protein and linked to these membrane sodium glucose cotransport systems . The first of these membrane transport proteins was named SGLT1 followed by the discovery of SGLT2 . Robert Krane also played a prominent role in this field . </P> <P> Specialized transmembrane proteins recognize the substance and allow it to move across the membrane when it otherwise would not, either because the phospholipid bilayer of the membrane is impermeable to the substance moved or because the substance is moved against the direction of its concentration gradient . There are two forms of active transport, primary active transport and secondary active transport . In primary active transport, the proteins involved are pumps that normally use the chemical energy in the form of ATP . Secondary active transport, however, makes use of potential energy, which is usually derived through exploitation of an electrochemical gradient . The energy created from one ion moving down its electrochemical gradient is used to power the transport of another ion moving against its electrochemical gradient . This involves pore - forming proteins that form channels across the cell membrane . The difference between passive transport and active transport is that the active transport requires energy, and moves substances against their respective concentration gradient, whereas passive transport requires no energy and moves substances in the direction of their respective concentration gradient . </P> <P> In an antiporter, one substrate is transported in one direction across the membrane while another is cotransported in the opposite direction . In a symporter, two substrates are transported in the same direction across the membrane . Antiport and symport processes are associated with secondary active transport, meaning that one of the two substances is transported against its concentration gradient, utilizing the energy derived from the transport of another ion (mostly Na, K or H ions) down its concentration gradient . </P>

When is active transport used in the body