Nonenzymatic Formation of Chl d from Chl a with Hydrogen Peroxide

In vitro Conversion of Vinyl to Formyl Groups in Naturally Occurring Chlorophylls

“…The biosynthesis of Chl d from Chl a must involve a different mechanism from the characterised CAO enzyme as it requires the conversion of the 3-vinyl group of Chl a to a 3-formyl group in Chl d rather than a methyl to formyl conversion as is the case for the synthesis of Chl b from Chl a . The oxidative cleavage of the 3-vinyl in Chl a (or its demetallated/dephytylated derivatives) to yield a formyl group can be achieved chemically in solvents using a strong oxidising agent1112 or using thiol-containing compounds under acidic conditions131415. Additionally, Chl d has been synthesised non-enzymatically in the presence of the cysteine protease papain1617.…”