Inhibition of the dehydratases encoded by pAK2.1, pAK5.1, and pAK7.1 by 1,3-propanediol. The dehydratase activity was determined as described in Materials and Methods with 100 mM 1,2-propanediol as the substrate in the presence of increasing concentrations of 1,3-propanediol (pAK2.1, ▴; pAK5.1, •; pAK7.1, ▪; C. freundii, ⊠). Activities are expressed relative to the initial activities obtained in the absence of 1,3-propanediol (pAK2.1, 14.0 U/ml; pAK5.1, 28.3 U/ml; pAK7.1, 26.1 U/ml; C. freundii, 9.8 U/ml).