H. Kindl
1969
Citations
1
Influential Citations
26
Citations
Quality indicators
Journal
European journal of biochemistry
Abstract
1 2-Hydroxyphenylacetic acid, a natural phenolic product found in the genus Astilbe, derives from the shikimic acid pathway via phenylpyruvic acid. The existence of two routes for the biosynthesis of 2-hydroxyphenylacetic acid could be demonstrated: a) A direct transformation of phenylpyruvic acid into 2-hydroxyphenylacetic acid involving a migration of the side chain. More than 95% of the tritium activity of 2-hydroxyphenylacetic acid was localized in position 5 when l-[4-3H]phenylalanine was fed. This complex oxidation is analogous to the known conversion of 4-hydroxyphenylpyruvic acid to homogentisic acid. b) A hydroxylation of [4-3H]phenylacetic acid to [4-3H]2-hydroxyphenylacetic acid was observed in vivo, and was also found to take place in vitro utilizing the system peroxidaseendiol-O2. 2 2,3-Dihydroxyphenylacetic acid and 2-hydroxy-3-methoxyphenylacetic acid could be established as natural products occurring in higher plants. Their chemical synthesis is described. By feeding experiments the following metabolic pathway is suggested: 2-hydroxyphenylacetic acid 2,3-dihydroxyphenylacetic acid 2-hydroxy-3-methoxyphenylacetic acid. 3,4-Dihydroxyphenylacetic acid and 3-methoxy-4-hydroxyphenylacetic acid have been detected in extracts from various species of Astilbe and identified by paper chromatography. These two acids are metabolic products of 4-hydroxyphenylacetic acid. 3 Experiments with [U-14C]shikimic acid and dl-[α-14C]phenylalanine seem to indicate that the regulation of the biosynthesis of 2-hydroxyphenylacetic acid and 4-hydroxyphenylacetic acid takes place on the level of prephenic acid. 4 Preliminary results were obtained consistent with the hypothesis that in Astilbe chinensis the 2,3-dihydroxyphenylacetic acid, 3,4-dihydroxyphenylacetic acid and 2,5-dihydroxyphenylacetic acid are further metabolized and can be degraded by ring cleavage.