title: Factors affecting the stability of methanol dehydrogenase from Paracoccus denitrificans.
abstract: Methanol dehydrogenase from Paracoccus denitrificans was purified to homogeneity in two steps from the periplasmic fraction of methanol-grown cells. The enzyme was composed of subunits of M(r) 67,000 and 12,000, and non-covalently bound pyrroloquinoline quinone. It exhibited a pH optimum at pH values of 9.0 and above. It was not stable at pH greater than 9.0, but exhibited little loss of activity after prolonged incubation at pH values as low as 4.5. Methyl dehydrogenase was relatively stable to thermal denaturation. The thermal stability was enhanced by the presence of Ca2+ and diminished by the presence of EDTA. These data suggest a structural role for Ca2+ in this enzyme, similar to what has been observed with quinoprotein glucose and ethanol dehydrogenases.
authors.affiliation: Department of Biochemistry, University of Mississippi Medical Center, Jackson 39216-4505.
authors.forename: V L
authors.initials: VL
authors.lastname: Davidson
authors.forename: J
authors.initials: J
authors.lastname: Wu
authors.forename: B
authors.initials: B
authors.lastname: Miller
authors.forename: L H
authors.initials: LH
authors.lastname: Jones
mesh_terms: D000429:Alcohol Oxidoreductases / Q000737:chemistry* / Q000187:drug effects / Q000302:isolation & purification; D002118:Calcium / Q000494:pharmacology; D004492:Edetic Acid / Q000494:pharmacology; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D045542:PQQ Cofactor; D010231:Paracoccus denitrificans / Q000187:drug effects / Q000201:enzymology*; D015363:Quinolones / Q000737:chemistry; D013329:Structure-Activity Relationship; D013696:Temperature
chemical_list: D015363:Quinolones; D045542:PQQ Cofactor; D004492:Edetic Acid; D000429:Alcohol Oxidoreductases; C019641:alcohol dehydrogenase (acceptor); D002118:Calcium