Chlorophyll pheophytin

Turkmen, N. et al.. Effects of cooking methods on chlorophylls, pheophytins and colour of selected green vegetables, hit. J. Food Sci. TechnoL, 41, 281, 2006. 

Usually, HPLC analysis resolves four peaks identified by co-chromatography with authentic standards as copper pheophorbide a, Cn(II) chlorin e6, Cn(II) chlorin e4, Cu rhodin g7, and their degradation products, but a sum of other colored components can also be found, for example, native chlorophylls, pheophytins, pheophor-bides, and rodochlorins (free carboxyl forms of pheophorbides) besides epimers, allomers, and degradation products that have been only tentatively identified. 

A. Cichelli and G.P. Pertesana, High-performance liquid chromatographic analysis of chlorophylls, pheophytins and carotenoids in virgin olive oils chemometric approach to variety classification. J. Chromatogr.A 1046 (2004) 141-146. 

Photosystem II (Fig. 1) bears many similarities to the much simpler reaction center of purple bacteria. Remarkable is, however, the increase in complexity at the protein level. In a recent review on the evolutionary development of the type 11 reaction centres340 this was attributed to the invention of water-splitting by PS II and the necessity to protect and repair the photosynthetic machinery against the harmful effects of molecular oxygen. The central part of PS II and the bRC show a highly conserved cofactor arrangement,19 see Fig. 1. These cofactors are arranged in two branches bound to two protein subunits, L/M and D1/D2 in bRC and PS II, respectively. On the donor side a closely related pair of chlorophylls or bacteriochlorophylls exists the acceptors comprise monomeric chlorophylls, pheophytins (Ph) and 2 quinones QA and QB. Qa and Qb are plas-... 

Phenylspiro[furan-2(3 H), 1 -phthalan]-3,3-dione. see Fluorescamine Pheophorbides. see also Chlorophylls Pheophytins. see also Chlorophylls Phospholipids, 523... 

Fluorescence quenching studies showed that chlorophyll a molecules are solubilized by dimyristoylphosphatidylcholine (DMPC) only up to concentrations of around 1 mol %. Excess molecules precipitate almost exclusively in domains containing chlorophyll. Pheophytin a solubility in liquid DMPC amounts to about 10 mol %. 

A (197) and B (198) were reported as new chlorophyll derivatives from A. elegans [168,292] and aristophyll C (199) was also found as a new chlorophyll in A. heterophylla [232], Methyl pheophorbide-a (200) and methyl 21-hydroxy-(21f )-pheophorbide-a (201) were isolated from A. cucurbitifolia [56,159], A known chlorophyll, pheophytin-a (202), was isolated from A. kaempferi [229]. Another new pheophytin-a derivative described from A. heterophylla is 132-hydroxy-(1325)-pheophytin-a (203) [232], Incidentally, all these chlorophylls were isolated by our group from Aristolochia species collected in Taiwan. 

The reaction center of photosystem II (PSII) consists of three proteins The 32-kDa protein (32K, also referred to as D,), Dj, and cytochrome bjs, (1,2). It has several features in common with the reaction center from purple bacteria (3,4), including amino acid sequence homology in functional regions (3,5), arrangement of the transmembrane helices (6,7,8), and conservation of the binding sites for chlorophylls, pheophytins, quinones and a non-heme iron (3,4,6,7,9). Furthermore, 32K and the L-subunit of the bacterial reaction center are the site of triazine herbicide action (10-12), and point mutations at conserved residues in these proteins can confer herbicide resistance (3,13-15). 

Other TLC studies on fat-soluble chloroplast pigments from plant tissues include the following. Suzuki et al. (1987) studied the retention of chlorophylls, pheophytins, and pheophorbides in C,g TLC and HPLC systems. Stauber and Jeffrey (1988) examined the photosynthetic pigments of 51 species of tropical and subtropical diatoms by normal- and reversed-phase TLC. Cserhati (1988) determined the lipophilicity of some photosynthetic pigments using reversed-phase TLC on various impregnated layers with acetone and ethanol as the mobile phase. Heimler et al. (1989) quantitatively determined chlorophylls in spruce needles by densitometry on cellulose layers. 

Hyvarinen, K. and Hynninen, P.H., Liquid chromatographic separation and mass spec-trometric identification of chlorophyll b allomers, J. Chromatogr. A, 837, 107, 1999. Constantin, E. et al.. Electron-impact and chemical ionization mass-spectrometry of chlorophylls, pheophytins and phaeophorbides by fast desorption on a gold support. Bull. Soc. Chim. Fr., 7-8, 303, 1981. 

Perkins, H.J. and Roberts, D.W.A., Purification of chlorophylls, pheophytins and pheophorbides for specific activity determinations, Biochim. Biophys. Acta, 58, 486, 1962. 

Seppanen, C.M., Rahmani, M., and Csallany, A.S., Simultaneous determination of chlorophylls, pheophytins, beta-carotene, tocopherols, and tocotienols in olive and soybean oils by high-performance liquid chromatography. J. Food Sci., 68, 1644, 2003. Torsi, G., Chiavari, G., and Lippolis, M.T., Quantitation without calibration curves using HPLC with nondestructive detectors, LC-GC Inti., 5, 37, 1992. 

From these fractions, chlorophylls, pheophytins, sterols and carotenoids were identified (data not shown), and the suppressive effects of identified conq>ounds on transformation of AhR by TCDD were examined by EMSA as shown in Table. Chlorophylls showed a strong suppressive effect, though pheophytins showed weak effects. Since both chlorophylls and pheophytins have porphyrin rings, the structure of the rings may not be associated with their suppressive effects. Regarding carotenoids contained in fraction-7, -8 and -9, lutein suppressed effectively, while sterols and carotenes did not affect. 

The spectra in Fig, 4 show, that the fractions 30-33 indeed contain chlorophyll attached to the protein, whereas the free chlorophyll (pheophytin) appears in the fractions 42-52. Fig, 5 shows the fractions analyzed in SDS-PAGE, It demonstrates that fractions 30 - 33 contain the single subunit 1 in the 50 kD form. The other fractions appear in fractions 38 - 44 ... 

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