The metabolism of β-phenylpropionic acid by an Achromobacter

Abstract

When a species of Achromobacter grew with [beta]-phenylpropionate as carbon source, 2-hydroxy-[beta]-phenylpropionate and 2,3-dihydroxy-[beta]-phenylpropionate appeared in the growth medium. The concentrations of these compounds were maximal during exponential growth. The cells contained an oxygenase that required Fe2+ ions and cleaved the benzene nucleus between the adjacent carbon atoms that bear the side chain and one hydroxyl group of 2,3-dihydroxy-[beta]-phenyl-propionate. The ring-fission product, formed with the consumption of 1mol. of oxygen/mol. of substrate, was isolated and a chemical structure assigned. Sephadex-treated cell extracts converted 1mol. of this compound into 1mol. of 4-hydroxy-2-oxovalerate without oxygen consumption; succinic acid was also formed. When Mn2+ ions or Mg2+ ions were added, dialyzed extracts converted 4-hydroxy-2-oxovalerate into pyruvate and acetaldehyde, but the reaction did not proceed to completion.