The enzyme participates in chlorophyll degradation, which occurs during leaf senescence and fruit ripening in higher plants. The reaction requires reduced ferredoxin, which is generated from NADPH produced either through the pentose-phosphate pathway or by the action of photosystem I [1,2]. This reaction takes place while red chlorophyll catabolite is still bound to EC 1.14.15.17, pheophorbide a oxygenase [3]. Depending on the plant species used as the source of enzyme, one of two possible C-1 epimers of primary fluorescent chlorophyll catabolite (pFCC), pFCC-1 or pFCC-2, is normally formed, with all genera or species within a family producing the same isomer [3,4]. After modification and export, pFCCs are eventually imported into the vacuole, where the acidic environment causes their non-enzymic conversion into colourless breakdown products called non-fluorescent chlorophyll catabolites (NCCs) [2].
