The Royal Swedish Academy of Sciences announced that Koichi Tanaka has, along with two other pioneering scientists, been awarded the Nobel Prize in Chemistry 2002.
Koichi Tanaka, of Shimadzu Corp, Kyoto, Japan, was jointly awarded one half of the prize with John B Fenn of Virginia Commonwealth University for their development of soft desorption ionization methods in mass spectrometric analyses of biological macromolecules. Tanaka's approach has become fundamental in the standard methods (MALDI, SELDI and DIOS) for structural analyses of proteins, DNA and carbohydrates which make it possible to characterize the components of biological systems. Many of the laser desorption technologies on the market today have their foundations in Tanaka's work.
This year's Chemistry Prize focuses on powerful analytical methods for studying biological macromolecules, such as proteins. Tanaka is the architect of a soft ionization technique that the Royal Swedish Academy of Sciences describes as 'hovering through blasting'. In 1987, at an Oriental mass spectrometry symposium, Tanaka proved that protein molecules could be ionized using the soft laser desorption technique. A year later, the scientific community saw the full publication of his seminal paper.
Soft laser desorption is based on the bombardment of a solid of viscous phase sample with a laser pulse. The sample takes up energy from this pulse and the components or ions desorbed from the surface. An electrical field accelerates the ions which are detected by a mass analyzer. The differentiation of ions is based on the time it takes for them to fly through a flight tube, which is dependent on their mass/charge (m/z) ratios - the larger the ions, the slower its velocity and the longer it takes to make its trajectory.
Combining MALDI with a time-of-flight mass spectrometric detection has signified a monumental step in molecular weight determination of biological macromolecules. The Royal Swedish Academy of Sciences has recognized Tanaka's technology for what it is -a cornerstone of proteomics.