Pathway: 4-hydroxybenzoate biosynthesis

Mammals |FRAME: 4-hydroxybenzoate 4-hydroxybenzoate| from |FRAME: TYR L-tyrosine|, as described in this pathway. This important pathway has received surprisingly little attention, and has not been characterized very well. A pathway for the conversion of |FRAME: TYR L-tyrosine| to |FRAME: 4-hydroxybenzoate 4-hydroxybenzoate| was proposed already in 1960, based on urinary excretion studies on animals administered with various phenolic acids and the incorporation of radiolabeled phenolic acids into ubiquinone by rat liver and yeast |CITS: [Booth60]|. Based on those results, it was suggested that |FRAME: TYR L-tyrosine| is converted to |FRAME: P-HYDROXY-PHENYLPYRUVATE 4-hydroxyphenylpyruvate|, which is then modified to |FRAME: 4-HYDROXYPHENYLLACTATE 4-hydroxyphenyllactate| and |FRAME: COUMARATE 4-coumarate| |CITS: [Booth60]|. These results were confirmed by additional work performed with rat |CITS: [14081946][14253463][6369767]|. The later part of the pathway, starting with |FRAME: COUMARATE 4-coumarate|, has not been studied much in animals. In plants it has been shown that |FRAME: COUMARATE 4-coumarate| is converted to |FRAME: 4-hydroxybenzoate 4-hydroxybenzoate| either directly (see |FRAME: PWY-6431 4-hydroxybenzoate biosynthesis IV|) or via CoA derivatives such as |FRAME: P-COUMAROYL-COA 4-coumaroyl-CoA| and |FRAME: CPD-201 4-hydroxybenzoyl-CoA| (see |FRAME: PWY-6435 4-hydroxybenzoate biosynthesis V|).