Metabolism, chlorophylls

Rudiger, W., Chlorophyll metabolism from outer space down to the molecular level, Phytochemistry, 46, 1151, 1997. 

Roca, M. and Mmguez-Mosquera, M.L, Involvement of chlorophyllase in chlorophyll metabolism in olive varieties with high and low chlorophyll content, Physiol. Plant, 117, 459, 2003. 

Biotin metabolism Folate biosynthesis One carbon pool by folate Retinol metabolism Porphyrin and chlorophyll metabolism Terpenoid biosynthesis Xenobiotics metabolism Ubiquinone biosynthesis Flavonoids, stilbene, and lignin biosynthesis... 

Rudiger W, Grimm B. Chlorophyll metabolism, an overview. In Chlorophylls and Bacteriochlorophylls Biochemistry, Biophysics, Functions and Applications. Grimm B, Porra R, Rudiger W, Scheer H, eds. 2006. Springer, Dordrecht, The Netherlands, pp. 133-146. 

Phytol (3, 7, 11, 15-tetramethylhexadec-2-en-l-ol) is a diterpene, a member of the group of branched-chain imsaturated alcohols (Figure 13). Being the product of chlorophyll metabolism in plants, phytol is widely spread in nature. Phytol probably originates in com oil from chlorophylls. 

Mitrakos, K. (1961). The participation of the red far-red reaction system in chlorophyll metabolism. Physiol. Plantarum 14, 497-503. 

Diets high in red meat and low in green vegetables have been associated with increased colon cancer risk and the opposite has been postulated for diets rich in green vegetables. A plausible explanation for an increased colon cancer risk is that dietary haem is metabolized in the gut to a factor that increases colonic cytotoxicity and hyperproliferation, which are considered important risk factors in the development of cancer. In this sense, it has been shown that spinach and isolated natural chlorophyll, but not sodium-copper chlorophyUin, prevented the proliferation of colonic cells and may therefore reduce colon cancer risk. It has been speculated that haem and chlorophylls, due to their hydrophobicity, form a complex, thus preventing the metabolism of haem. ... 

In plant plastids, GGPP is formed from products of glycolysis and is eight enzymatic steps away from central glucose metabolism. The MEP pathway (reviewed in recent literature - ) operates in plastids in plants and is a preferred source (non-mevalonate) of phosphate-activated prenyl units (IPPs) for plastid iso-prenoid accumulation, such as the phytol tail of chlorophyll, the backbones of carotenoids, and the cores of monoterpenes such as menthol, hnalool, and iridoids, diterpenes such as taxadiene, and the side chains of bioactive prenylated terpenophe-nolics such as humulone, lupulone, and xanthohumol. The mevalonic pathway to IPP that operates in the cytoplasm is the source of the carbon chains in isoprenes such as the polyisoprene, rubber, and the sesquiterpenes such as caryophyllene. 

The phytotoxic effect may be due to interference with chlorophyll production or other metabolic processes. The observations noted in Table VI suggest that there is some recovery at 7 days from the conditions described in Table V for 5 days. However, this is not the case, since the same chlorotic effect is noted for the new fronds which were the first to emerge early in the observation period. This indicates that the phenomenon is due to the growth of new fronds which have not yet been exposed to the test media. 

The reported (14) mechanisms of action of allelochemlcals Include effects on root ultrastructure and subsequent Inhibition of Ion absorption and water uptake, effects on hormone-induced growth, alteration of membrane permeability, changes In lipid and organic acid metabolism, inhibition of protein synthesis and alteration of enzyme activity, and effects on stomatal opening and on photosynthesis. Reduced leaf water potential Is one result of treatment with ferulic and p-coumaric acids (15). Colton and Einhellig (16) found that aqueous extracts of velvetleaf (Abutllon theophrastl Medic.) Increased diffusive resistance In soybean fGlycine max. (L.) Merr.] leaves, probably as a result of stomatal closure. In addition, there was evidence of water stress and reduced quantities of chlorophyll In Inhibited plants. 

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