Open AccessStructure and Activity of the Prosthetic Group of Methanol Dehydrogenase
Author(s) -
DUINE Johannis A.,
FRANK Jzn Johannes,
VERWIEL P. Eugène J.
Publication year - 1980
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1980.tb04711.x
Subject(s) - methanol dehydrogenase , quinone , methanol , chemistry , dehydrogenase , lactate dehydrogenase , ring (chemistry) , cofactor , enzyme , stereochemistry , group (periodic table) , molecule , quinoline , biochemistry , organic chemistry
The reconstitutive ability of the isolated prosthetic group of methanol dehydrogenase with the apoenzyme of glucose dehydrogenase and the results of electron spin resonance measurements suggest that the prosthetic group has not been modified during the isolation. This result, and the properties of the directly isolated prosthetic group and derivatives, confirm the suggestion that its structure is 2,7,9‐tricarboxy‐1 H ‐pyrrolo[2,3‐ f ]quinoline‐4,5‐dione. From the activity shown by derivatives of the prosthetic group and of structural analogues in the apoenzyme test it is concluded that the o ‐quinone structure is essential for activity. Hence the trivial name pyrrolo‐quinoline quinone would be appropriate. The testing of the analogues also shows that the pyrrolo ring and the 9‐carboxylic acid group are not essential for activity as they can be replaced by a pyridinol ring and a 9‐hydroxy group respectively. The determination of the molar absorption coefficient of the prosthetic group (18400 M −1 cm −1 at 249 nm) enables its quantitative analysis. Thus it could be established that methanol dehydrogenase contains one prosthetic group per enzyme molecule. The consequences of this result in relation to already known properties of this ‘quinoprotein’ dehydrogenase are discussed.