Chemical and mutational modification of histidines in violaxanthin de-epoxidase from Spinachcia oleracea.
The violaxanthin de-epoxidase (VDE) gene from spinach (Spinacia oleracea) was cloned, sequenced (GenBank AJ 250433), and expressed in Escherichia coli. The highest obtained conversion rate of violaxanthin was 86 nmol s-1 per litre of growth medium, corresponding to an amount of active enzyme of 0.4 mg l-1. Sequence comparison between VDE from different species were made and particular interest was