Quinone compounds are able to replace molecular oxygen as terminal electron acceptor in phytoene desaturation in chromoplasts of Narcissus pseudonarcissus L.

Abstract

The desaturation of phytoene to ζ‐carotene and of ζ‐carotne to lycopene employs molecular oxygen as the terminal electron acceptor. 2,3,5,6‐Tetramethyl‐1,4‐benzoquinone (duroquinone) and other artificial quinones are able to replace oxygen, which demonstrates that oxygen does not act in a mixed‐function oxygenase‐like mechanism at the desaturase itself, but at a spatially separate site. Evidence for additional redox elements mediating between desaturase and oxygen is presented. Copyright © 1990, Wiley Blackwell. All rights reserved