The generation of an organic free radical in substrate‐reduced pig kidney diamine oxidase‐cyanide

FEBS Letters

Dooley, David M.²  Peisach, Jack¹  McGuirl, Michele A.²  McCracken, John¹ 

[1] Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA;Department of Chemistry, Amherst College, Amherst, MA 01002, USA

关键词: Amine oxidase;    Organic free radical;    EPR;    Optical absorption spectrum;    Pyrroloquinolinequinone;   

DOI  :  10.1016/0014-5793(87)80069-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

When the cyanide complex of the copper protein, pig kidney diamine oxidase, is reduced anaerobically by cadaverine (1,5-diaminopentane), the broad, 480 nm absorption band characteristic of the resting enzyme is bleached and a new absorption spectrum with features at 457, 429, 403 (shoulder), 360 (shoulder) and 332 nm appears. Concomitantly, the EPR spectrum of the enzyme Cu(II)-CN complex decreases in intensity and a new signal is observed that is attributable to an organic free radical. The g values and hyperfine splittings are similar to those previously assigned to a free radical observed when the cyanide complex of lentil seedling diamine oxidase is reacted with the substrate p-dimethylaminomethylbenzylamine [(1984) FEBS Lett. 176, 378–380]. The optical absorption and EPR spectra of the organic radical observed in both proteins are consistent with the same semiquinone-type structure, as expected if pyrroloquinolinequinone (PQQ) is the bound cofactor found in both enzymes.

【 授权许可】

Unknown