Reaction: (1) violaxanthin = capsorubin
(2) antheraxanthin = capsanthin
For diagram click here (mechanism).
Other name(s): CCS; ketoxanthophyll synthase; capsanthin-capsorubin synthase
Systematic name: violaxanthin—capsorubin isomerase (ketone-forming)
Comments: This multifunctional enzyme is induced during chromoplast differentiation in plants [1]. Isomerization of the epoxide ring of violaxanthin gives the cyclopentyl-ketone of capsorubin or capsanthin.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 162032-85-1
References:
1. Bouvier, F., Hugueney, P., d'Harlingue, A., Kuntz, M. and Camara, B. Xanthophyll biosynthesis in chromoplasts: isolation and molecular cloning of an enzyme catalyzing the conversion of 5,6-epoxycarotenoid into ketocarotenoid. Plant J. 6 (1994) 45-54. [PMID: 7920703]
2. Lefebvre, V., Kuntz, M., Camara, B. and Palloix, A. The capsanthin-capsorubin synthase gene: a candidate gene for the y locus controlling the red fruit colour in pepper. Plant Mol. Biol. 36 (1998) 785-789. [PMID: 9526511]
3. Xu, C.J., Chen, D.M. and Zhang, S.L. [Molecular cloning of full length capsanthin/capsorubin synthase homologous gene from orange (Citrus sinensis).] Shi Yan Sheng Wu Xue Bao 34 (2001) 147-150. [PMID: 12549109] [Article in Chinese]