Peter Agre and Roderick MacKinnon’s research has provided crucial information, particularly about illnesses affecting the kidneys, heart, muscles and nervous system.
The Nobel jury said the 2003 prize, worth over a million dollars, illustrates how contemporary biochemistry reaches down to the atomic level “in its quest to understand the fundamental process of life”.
"Peter Agre and Roderick MacKinnon have contributed to fundamental chemical knowledge … and have opened our eyes to a fantastic family of molecular machines," the Nobel jury said on Wednesday.
While Nobel science prizes often go to elderly scientists who conducted their prize-winning research decades before their award, Agre and MacKinnon are young and their research is recent.
MacKinnon made his key discovery just five years ago and Agre was honoured for work conducted in 1988.
Their discoveries have clarified how salts and water are transported out of and into the cells of the body.
For example, we now know how kidneys recover water from primary urine and how the electrical signals in nerve cells are generated and spread.
This has many practical applications, and may even help explain the thousands of deaths resulting from this year's European heatwave when problems maintaining body fluid balance led to widespread dehydration.
At 47, MacKinnon isthe youngest
scientists to receive the award
Understanding how water travels between cells could be vital to prevent such a disaster in future.
As early as the middle of the 19th century, it was suspected that the body's cells must have specific channels for transporting water.
However, it was not until 1988 that Agre succeeding in isolating a membrane protein that he, about a year later, realised must be the long sought-after water channel.
Spin off research
His discovery opened the door to a whole series of biochemical, physiological and genetic studies of water channels in bacteria, plants and mammals.
Researchers can now follow a water molecule on its way through the cell membrane and understand why only water, and not other small molecules or ions (salts), can pass.
The other type of membrane channel which is the subject of this year's Chemistry Prize is the ion channel.
"Peter Agre and Roderick MacKinnon have contributed to fundamental chemical knowledge … and have opened our eyes to a fantastic family of molecular machines"
Nobel prize jury
MacKinnon "surprised the whole research community", the jury said, when he in 1998 was able to determine the spatial structure of a potassium channel.
"Thanks to this contribution we can 'see' ions flowing through channels that can be opened and closed by different cellular signals," it said.
Ion channels control the pace of the heart, regulate hormone secretion and generate the electrical impulses that enable the transfer of information in the nervous system.
This year's Nobel season opened last week with the awarding of the Literature Prize to South African author J.M. Coetzee.
On Monday, US scientist Paul Lauterbur and Sir Peter Mansfield of Britain won the Medicine Prize for discoveries about magnetic resonance imaging.
The next day, the Physics Prize was awarded to three quantum physicists, Alexei Abrikosov, Vitaly Ginzburg and Anthony Leggett, for their work on the theory of superconductors and superfluids.