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Koichi Tanaka

Koichi Tanaka
BornAugust 3 1959 (1959-08-03) (age 53)
Toyama, Japan
Citizenship Japan
FieldEngineer and Chemist
InstitutionsShimadzu Corporation
Alma materTohoku University
Known forSoft laser desorption
Notable prizes Nobel Prize for Chemistry (2002)
First post-war- born Laureate, second youngest, first without advanced degree

Koichi Tanaka (田中 耕一 Tanaka Kōichi, born August 3, 1959) is a Japanese scientist who won the Nobel Prize in Chemistry in 2002 for developing a novel method for mass spectrometric analyses of biological macromolecules.[1]

Tanaka was born and raised in Toyama, Japan. In 1983, he graduated from Tohoku University with a bachelor's degree in engineering. As of 2006, he is the only person without a post-bachelor's degree to have won a Nobel Prize in a scientific field. After graduation, he joined Shimadzu Corporation, where he engaged in the development of mass spectrometers.

For mass spectrometry analyses of a macromolecule, such as a protein, the analyte must be ionized and vaporized by laser irradiation. The problem is that the direct irradiation of an intense laser pulse on a macromolecule causes cleavage of the analyte into tiny fragments and the loss of its structure. In February 1985, Tanaka found that by using a mixture of ultra fine metal powder in glycerol as a matrix, an analyte can be ionized without losing its structure. His work was filed as a patent application in 1985, and after the patent application was made public reported at the Annual Conference of the Mass Spectrometry Society of Japan held in Kyoto, Japan, in May 1987 and became known as soft laser desorption (SLD).[2]

However, there was some criticism about his winning the prize, saying that contribution by two German scientists, Franz Hillenkamp and Michael Karas was also big enough not to be dismissed, and therefore they should also be included as prize winners. This is because they first reported in 1985 a method, with higher sensitivity using a small organic compound as a matrix, that they named Matrix-Assisted Laser Desorption/Ionization (MALDI).[3] Also Tanaka's SLD is not used currently for biomolecules analysis, meanwhile MALDI is widely used in mass spectrometry research laboratories. But while MALDI was developed prior to SLD, it was not used to ionize proteins until after Tanaka's report.[4]


  1. ^ Tanaka, K.; Waki, H.; Ido, Y.; Akita, S.; Yoshida, Y.; Yoshida, T. (1988). "Protein and Polymer Analyses up to m/z 100 000 by Laser Ionization Time-of flight Mass Spectrometry". Rapid Commun Mass Spectrom 2 (20): 151-3.
  2. ^ Markides, K; Gräslund, A. Advanced information on the Nobel Prize in Chemistry 2002 (PDF).
  3. ^ Karas, M.; Bachmann, D.; Hillenkamp, F. (1985). "Influence of the Wavelength in High-Irradiance Ultraviolet Laser Desorption Mass Spectrometry of Organic Molecules". Anal. Chem. 57: 2935-9.
  4. ^ Karas M, Hillenkamp F (1988). "Laser desorption ionization of proteins with molecular masses exceeding 10,000 daltons". Anal. Chem. 60 (20): 2299-301. PMID 3239801.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Koichi_Tanaka". A list of authors is available in Wikipedia.
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