Dopamine β‐hydroxylase from bovine adrenal medulla contains covalently‐bound pyrroloquinoline quinone

FEBS Letters

Jongejan, Jacob A.¹  Duine, Johannis A.¹  van der Meer, Robert A.¹ 

[1] Department of Microbiology and Enzymology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands

关键词: Dopamine β-hydroxylase;    Pyrroloquinoline quinone;    Hydrazine;    Cofactor;    Quinoprotein;    Copper-containing enzyme;   

DOI  :  10.1016/0014-5793(88)80838-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Treatment of homogeneous dopamine β-hydroxylase (DBH) preparations from bovine adrenals with the inhibitor phenylhydrazine (PH) changed the structureless absorption spectrum of DBH into spectra with a maximum at 350 nm. A product with this absorption spectrum could be detached with pronase, enabling its isolation. It appeared to be the C(5) hydrazone of pyrroloquinoline quinone (PQQ) and PH, as judged from its properties and the fact that it could be transformed into PQQ itself. From the yield obtained a ratio of 0.85 PQQ per enzyme subunit was calculated. In contrast to copper-quinoprotein amine oxidases (EC 1.4.3.6), hydrazone formation in DBH did not require saturation of the mixture with O₂. DBH is the first copper-quinoprotein hydroxylase found so far. The implications of this finding for the current views on mechanism of action and inhibition by hydrazines are discussed. The success of the recently developed ‘hydrazine method’ [(1987) FEBS Lett. 221, 299-304] for all different types of amine oxidoreductases, suggest that the method could also be applied to other enzymes for which hydrazines are inhibitors and where the identity of the cofactors has not been established or the presence of PQQ is suspected.

【 授权许可】

Unknown