Abstract
The biosynthetic pathway of Chl, probably the most important pigment in the biosphere, has been studied in considerable detail and is mentioned in plant physiology textbooks. Oddly enough, however, the breakdown of Chl is barely mentioned. Yet, as pointed out by Hendry et al. (1987), an estimated one billion tons of Chl are broken down every year, seemingly without leaving a trace. The only enzyme that is taught is chlorophyllase, discovered by Arthur Stoll in 1912, which cleaves Chl into phytol and Chlide, the Mg-porphyrin moiety of Chl. For most of the subsequent 80 years, chlorophyllase has been the only known part of the catabolic system. Until quite recently a11 the subsequent steps of Chlide breakdown remained undiscovered because no one was able to identify the breakdown products. We now know that the reason these products remained undetected is quite trivial: they are colorless. In mammals, the bile pigments biliverdin and bilirubin are colored breakdown products of heme; by analogy, plant biochemists may have expected the breakdown products of Chlide to be colored as well, but this is not the case, which is probably why they were overlooked for so long. The identification of the structures of these colorless catabolites has, in the last few years, led to the elucidation of the pathway of Chl catabolism in the senescing leaves of higher plants.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.