A new rearrangement reaction in tyrosine metabolism.

Human faecal specimens were incubated under anaerobic conditions with several dideuterated tyrosine metabolites. 3-(4-Hydroxy[3,5-2H2]phenyl)propionic acid and 3-(4-hydroxy[3,5-2H2]phenyl)lactic acid yielded the rearrangment product 3-(3-hydroxy[2,4-2H2]phenyl)propionic acid. The starting materials as well as the product all contained two deuterium atoms both ortho to the hydroxyl group. Therefore the rearrangement reaction must depend on a shift of the side chain.