biostudies-literatureUnknown67(21)Bruno MKing Abdullah University of Science and TechnologyThe Arabidopsis carotenoid cleavage dioxygenase 4 (AtCCD4) is a negative regulator of the carotenoid content of seeds and has recently been suggested as a candidate for the generation of retrograde signals that are thought to derive from the cleavage of poly-cis-configured carotene desaturation intermediates. In this work, we investigated the activity of AtCCD4 in vitro and used dynamic modeling to determine its substrate preference. Our results document strict regional specificity for cleavage at the C9-C10 double bond in carotenoids and apocarotenoids, with preference for carotenoid substrates and an obstructing effect on hydroxyl functions, and demonstrate the specificity for all-trans-configured carotenes and xanthophylls. AtCCD4 cleaved substrates with at least one ionone ring and didJournal of experimental botany5993-6005https://www.ebi.ac.uk/biostudies/studies/S-EPMC5100015biostudies-literatureEnzymatic study on AtCCD4 and AtCCD7 and their potential to form acyclic regulatory metabolites.PMC5100015Fehling-Kaschek MKoschmieder JWuest FSchaub PBruno MAl-Babili STimmer JBeyer PfalseEnzymatic study on AtCCD4 and AtCCD7 and their potential to form acyclic regulatory metabolites.The Arabidopsis carotenoid cleavage dioxygenase 4 (AtCCD4) is a negative regulator of the carotenoid content of seeds and has recently been suggested as a candidate for the generation of retrograde signals that are thought to derive from the cleavage of poly-cis-configured carotene desaturation intermediates. In this work, we investigated the activity of AtCCD4 in vitro and used dynamic modeling to determine its substrate preference. Our results document strict regional specificity for cleavage at the C9-C10 double bond in carotenoids and apocarotenoids, with preference for carotenoid substrates and an obstructing effect on hydroxyl functions, and demonstrate the specificity for all-trans-configured carotenes and xanthophylls. AtCCD4 cleaved substrates with at least one ionone ring and did2016-01-01T00:00:00Z2016 Nov2025-04-22T08:58:30.212Z2019-03-27T02:28:31ZS-EPMC51000152781107510.1093/jxb/erw356