title: Purification and properties of crystalline 3-hydroxybutyrate dehydrogenase from Rhodopseudomonas spheroides.
abstract: 1. The purification and crystallization of 3-hydroxybutyrate dehydrogenase from extracts of Rhodopseudomonas spheroides is described. 2. The molecular weight was calculated to be 85000 by sedimentation equilibrium. 3. Although the enzyme is stable at 0-4 degrees , dilute solutions are rapidly inactivated at 37 degrees ; NADH(2) or Ca(2+) ions prevent this inactivation. 4. The enzyme is extremely sensitive to mercurials, but can be protected by NADH(2) or Ca(2+) ions. 5. From studies on p-hydroxymercuribenzoate binding it is estimated that the enzyme contains 5-6 moles of rapidly reacting thiol groups/mole. 6. d-Lactate and dl-2-hydroxybutyrate are competitive inhibitors of d-3-hydroxybutyrate oxidation. 7. The properties of the crystalline enzyme are compared with those of 3-hydroxybutyrate dehydrogenase preparations from other sources.
mesh_terms: D000963:Antimetabolites / Q000494:pharmacology; D002845:Chromatography; D002850:Chromatography, Gel; D003460:Crystallization; D006863:Hydrogen-Ion Concentration; D006884:Hydroxybutyrate Dehydrogenase / Q000032:analysis* / Q000378:metabolism; D007700:Kinetics; D008970:Molecular Weight; D009243:NAD; D012241:Rhodopseudomonas / Q000201:enzymology*; D013438:Sulfhydryl Compounds / Q000494:pharmacology
chemical_list: D000963:Antimetabolites; D013438:Sulfhydryl Compounds; D009243:NAD; D006884:Hydroxybutyrate Dehydrogenase