Neurospora shikimate pathway

The shikimate pathway was identified through the study of ultraviolet light-induced mutants of E. coli, Aerobacter aerogenes, and Neurospora. In 1950, using the penicillin enrichment technique (Chapter 26), Davis obtained a series of mutants of E. coli that would not grow without the addition of aromatic substances.4 5 A number of the mutants required five compounds tyrosine, phenylalanine, tryptophan, p-aminobenzoic acid, and a trace of p-hydroxybenzoic acid. It was a surprise to find that the requirements for all five compounds could be met by the addition of shikimic acid, an aliphatic compound that was then regarded as a rare plant acid. Thus, shikimate was implicated as an intermediate in the biosynthesis of the three aromatic amino acids and of other essential aromatic substances.6 7... 

The shikimate pathway was identified through the study of ultraviolet light-induced mutants of E. coli, Aerobacter aerogenes, and Neurospora. In 1950, using the penicillin enrichment technique (Chapter 26), Davis obtained a series of mutants of E. coli that would not grow without the addition of aromatic substances. ... 

In a reaction that does not involve a monohydroxyphthalic acid, 4,5-dihy-droxyphthalic acid is formed. This is decarboxylated to protocatechuic acid the decarboxylation is unusual in that previously described reactions eliminating carboxyl groups from aromatic rings had all been oxidative. A biosynthesis involving a major metabolic pathway was indicated by the accumulation of protocatechuic acid by a Neurospora mutant blocked in the conversion of dihydroshikimic acid to shikimic acid (Gross et al, 1956). 

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