title: Resolution of the coenzyme B-12-dependent dehydratases of Klebsiella sp. and Citrobacter freundii.
abstract: Diol dehydratase (1,2-propanediol hydro-lyase, EC 4.2.1.28) and glycerol dehydratase (glycerol hydro-lyase, EC 4.2.1.30) are shown to be distinct, separable enzymes that occur individually or together in different strains of Klebsiella sp. Anaerobic growth with propan-1,2-diol induces diol dehydratase alone, whereas glycerol fermentation induces both enzymes in K. pneumoniae ATCC 25955 and in Citrobacter freundii NCIB 3735. The dehydratases can be resolved by polyacrylamide-gel electrophoresis or separated by anion-exchange chromatography alone. Sucrose density gradient centrifugation failed to distinguish the enzymes and indicated a molecular weight of 1.9 . 10(5) for both. The enzymes can be assayed individually, even when present in the same crude extract, using the 67-fold difference in their Km values for coenzyme B-12. For both enzymes inactivation kinetics are observed with glycerol as substrated, and monovalent cations influence both the inactivation rate and catalytic rate of the reaction.
mesh_terms: D002852:Chromatography, Ion Exchange; D002954:Citrobacter / Q000201:enzymology*; D003038:Cobamides / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004790:Enzyme Induction; D005990:Glycerol / Q000378:metabolism; D006836:Hydro-Lyases / Q000096:biosynthesis / Q000302:isolation & purification*; D007711:Klebsiella pneumoniae / Q000201:enzymology*; D011408:Propanediol Dehydratase / Q000096:biosynthesis / Q000302:isolation & purification*; D011409:Propylene Glycols / Q000378:metabolism
chemical_list: D003038:Cobamides; D011409:Propylene Glycols; D006836:Hydro-Lyases; D011408:Propanediol Dehydratase; C020671:glycerol dehydratase; D005990:Glycerol