Discovery of Carotenoids

Q Retinai was first synthesised in 1946 by the Dutch chemists Josef Ferdinand Arens (1914-2001) and David Adriaan van Dorp (1915-1995). [20] 

Otto Wallach (1847-1931) (laureate of the 1910 Nobel Pri2e for Chemistry) and Konrad Julius Bredt (1855-1937) recognised at the beginning ofthelast century thatterpenes are formed from Cs-buUding blocks (Fig. 7.13) semiterpenes (C5), monoterpenes (Cm), sesquiterpenes (C15), diterpenes (C2o) sesterterpenes 

13 The concepts of Bredt, Wallach andRuilika would nowadays be labelled as retrosynthesis or retrosyn-thetlc analysis . 

In 1921, Leopold Ruzicka (1887-1976) established the isoprene rule for the biosynthesis of terpenes through a formal head-to-tail coupling of isoprene units. Deviations from the rule (as in the case of chrysanthemic acid), as well as Wagner-Meerwein rearrangements, occasionally complicate the analysis. Only in the mid-1950s it could be shown that terpenes are indeed formed by active isoprene emits . [24,25] 

If the degradation of 1- C-labeUed glucose, e.g. in Escherichia coli or Alicydo-bacillus acidoterrestris, is investigated, the label is found at the terminal carbon atom (C-3) of glyceraldehyde-3-phosphate, pyruvate and acetyl-CoA. 

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A great deal of evidence for the Porter-Lincoln pathway of phytoene desaturation came with the advent of inhibitors of various steps of carotenoid biosynthesis, the discovery of carotenoid mutants in various organisms, and in vitro biosynthesis... 

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