Being the inquisitive type I did some searching. Not sure that chlorophyll breaks down into sugar. I did find some papers to direct me in the right direction (???) but will need more time to get my head around it.
Chlorophyll breakdown in higher plants[
" Chlorophyll breakdown is an important catabolic process of leaf senescence and fruit ripening. Structure elucidation of colorless linear tetrapyrroles as (final) breakdown products of chlorophyll was crucial for the recent delineation of a chlorophyll breakdown pathway which is highly conserved in land plants. Pheophorbide a oxygenase is the key enzyme responsible for opening of the chlorin macrocycle of pheophorbide a characteristic to all further breakdown products. Degradation of chlorophyll was rationalized by the need of a senescing cell to detoxify the potentially phototoxic pigment, yet recent investigations in leaves and fruits indicate that chlorophyll catabolites could have physiological roles. This review updates structural information of chlorophyll catabolites and the biochemical reactions involved in their formation, and discusses the significance of chlorophyll breakdown. This article is part of a Special Issue entitled: Regulation of Electron Transport in Chloroplasts.
Research Highlights
āŗ Chlorophyll is broken down in a multi-step pathway called PAO pathway. āŗ The PAO pathway operates during leaf senescence and fruit ripening. āŗ The end products of the pathway are fluorescent and nonfluorescent catabolites. āŗ The pathway aims to detoxify chlorophyll, but may also have physiological roles."
Another one.
Chlorophyll breakdown and chlorophyll catabolites in leaves and fruit
Chlorophyll metabolism probably is the most visible manifestation of life. Total annual turnover of chlorophyll has been estimated to involve more than 1000 million tons. Surprisingly, chlorophyll catabolism has remained an enigma until less than twenty years ago, when a colorless chlorophyll catabolite from senescent plant leaves was identified and its structure was elucidated. In the meantime, chlorophyll breakdown products have been identified in a variety of plant leaves and their structural features have been elucidated. Most recently, chlorophyll breakdown products have also been identified in some ripening fruit. Chlorophyll breakdown in vascular plants only fleetingly involves enzyme-bound colored intermediates. The stage of fluorescent catabolites is also passed rapidly, as these isomerize further to colorless nonfluorescent tetrapyrrolic catabolites. The latter accumulate in the vacuoles of de-greened leaves and are considered the final products of controlled chlorophyll breakdown. The same tetrapyrroles are also found in ripening fruit and are effective antioxidants. Chlorophyll breakdown leads to tetrapyrroles that appear to have physiologically beneficial chemical properties, and it may thus not merely be a detoxification process.
Research Progress in the Interconversion, Turnover and Degradation of Chlorophyll
Chlorophylls (Chls, Chl a and Chl b) are tetrapyrrole molecules essential for photosynthetic light harvesting and energy transduction in plants. Once formed, Chls are noncovalently bound to photosynthetic proteins on the thylakoid membrane. In contrast, they are dismantled from photosystems in response to environmental changes or developmental processes; thus, they undergo interconversion, turnover, and degradation. In the last twenty years, fruitful research progress has been achieved on these Chl metabolic processes. The discovery of new metabolic pathways has been accompanied by the identification of enzymes associated with biochemical steps. This article reviews recent progress in the analysis of the Chl cycle, turnover and degradation pathways and the involved enzymes. In addition, open questions regarding these pathways that require further investigation are also suggested.
Oh heck one more. This looks promising.
Comparative Proteomic Analysis by iTRAQ Reveals that Plastid Pigment Metabolism Contributes to Leaf Color Changes in Tobacco
Tobacco (Nicotiana tabacum), is a worldās major non-food agricultural crop widely cultivated for its economic value. Among several color change associated biological processes, plastid pigment metabolism is of trivial importance in postharvest plant organs during curing and storage. However, the molecular mechanisms involved in carotenoid and chlorophyll metabolism, as well as color change in tobacco leaves during curing, need further elaboration. Here, proteomic analysis at different curing stages (0 h, 48 h, 72 h) was performed in tobacco cv. Biāna1 with an aim to investigate the molecular mechanisms of pigment metabolism in tobacco leaves as revealed by the iTRAQ proteomic approach. Our results displayed significant differences in leaf color parameters and ultrastructural fingerprints that indicate an acceleration of chloroplast disintegration and promotion of pigment degradation in tobacco leaves due to curing. In total, 5931 proteins were identified, of which 923 (450 up-regulated, 452 down-regulated, and 21 common) differentially expressed proteins (DEPs) were obtained from tobacco leaves. To elucidate the molecular mechanisms of pigment metabolism and color change, 19 DEPs involved in carotenoid metabolism and 12 DEPs related to chlorophyll metabolism were screened. The results exhibited the complex regulation of DEPs in carotenoid metabolism, a negative regulation in chlorophyll biosynthesis, and a positive regulation in chlorophyll breakdown, which delayed the degradation of xanthophylls and accelerated the breakdown of chlorophylls, promoting the formation of yellow color during curing. Particularly, the up-regulation of the chlorophyllase-1-like isoform X2 was the key protein regulatory mechanism responsible for chlorophyll metabolism and color change. The expression pattern of 8 genes was consistent with the iTRAQ data. These results not only provide new insights into pigment metabolism and color change underlying the postharvest physiological regulatory networks in plants, but also a broader perspective, which prompts us to pay attention to further screen key proteins in tobacco leaves during curing.
Just realized, I thought this was the other thread where we were collecting papers. Shoot, now I have to find which one it was.
) and buried underground for 2~3 weeks until covered in black mold.
more cannabis specific research will be done.
