Abstract
Most of the enzymes which participate in chlorophyll metabolism have been already identified, but, the enzyme catalyzing the chlorophyll a -formation from 7-hydroxymethyl chlorophyll a (HMChl), which is the last step of the chlorophyll b -to-chlorophyll a conversion, remains to be identified. Previously, we showed that disruption of an Arabidopsis gene encoding a putative chloroplast protein with the flavin-binding motif resulted in accumulation of HMChl. In this study, we performed biochemical analysis with this recombinant protein which was produced in Escherichia coli. It showed that this protein contains FAD and iron molecules. Furthermore, we demonstrated that this protein catalyzes the conversion of HMChl to chlorophyll a in vitro. Taken together, we concluded that this protein is an HMChl reductase.
