Observations on the elimination of water from 2-hydroxy acids in the metabolism of amino acids by Clostridium sporogenes.

Cell-free extracts of Clostridium sporogenes catalyse the water elimination from (2R)-phenyllactate in the presence of one of the energy-rich compounds acetyl-CoA, acetylphosphate or ATP and coenzyme A. Water is eliminated from (2R)-phenyllactoyl-CoA without any of the aforementioned additions. Cinnamoyl-CoA also acts catalytically. One molecule of cinnamoyl-CoA causes the elimination of water from more than 8 molecules phenyllactate. This is important from an energetic point of view since less than 2 mol ATP are formed per 2-3 mol metabolized amino acids. An activation of the hydroxy group of the alpha-hydroxy acid in form of a phosphate ester can also be excluded for energetic reasons.