1.23.5.1	antheraxanthin + ascorbate	-	
1.23.5.1	antheraxanthin + ascorbate	de-epoxidation reaction of the xanthophyll cycle plays an important role in the protection of the chloroplast against photooxidative damage. Violaxanthin is bound to the antenna proteins of both photosystems. In photosystem II, the formation of zeaxanthin is essential for the pH-dependent dissipation of excess light energy as heat. Violaxanthin bound to site V1 and N1 is easily accessible for de-epoxidation, whereas violaxanthin bound to L2 is only partially and/or with the slower kinetics converible to zeaxanthin	
1.23.5.1	antheraxanthin + ascorbate	reaction of the xanthophyll cycle	
1.23.5.1	antheraxanthin + ascorbate	the violaxanthin/antheraxanthin cycle in Mantionella is caused by the interaction of the slow second de-epoxidation step and the relatively fast epoxidation of antheraxanthin to violaxanthin	
1.23.5.1	antheraxanthin + ascorbate	violaxanthin de-epoxidase and zeaxanthin epoxidase catalyze the addition and removal of epoxide groups in carotenoids of xanthophyll cycle in plants. The xanthophyll cycle is implicated in protecting the photosynthetoic apparatus from excessive light	
1.23.5.1	antheraxanthin + L-ascorbate	-	
1.23.5.1	additional information	the level of violaxanthin de-epoxidase changes in an inverse, nonlinear relationship with respect to the VAZ pool (violaxanthin + antheraxanthin + zeaxanthin), suggesting that enzyme levels can be indirectly regulated by the VAZ pool	
1.23.5.1	additional information	high concentrations of available violaxanthin, as found in enzyme assays with pure violaxanthin, lead to saturation of the VDE and a strong competition with the intermediate reaction product Ax, thus decreasing the ratio of the second deepoxidation rate to the first de-epoxidation rate	
1.23.5.1	additional information	spinach VDE is able to de-epoxidize violaxanthin bound to spinach or Mantoniella squamata light harvesting complexes in a comparable manner, rate constants for first and second reaction step, overview	
1.23.5.1	additional information	VDE is the first described putative plant lipocalin