Chlorophyll in higher plants

Figure F4.1.1 Structural differences between major classes of natural chlorophylls in higher plants and algae. Designation of pyrrole rings A-D and methene bridges a-5 is based on the nomenclature outlined by Fisher and Orth (1937).

Shimizu, S., R. Hotta, and E. Tamaki Metabolism of chlorophyll in higher plants. III. Pheophytins, as one of the color components of some tobacco varieties Bot. Mag. Tokyo 79 (1966) 560-565. 

Chlorophyll h, in which the 3-Me group is replaced by -CHO this occurs in higher plants and green algae, the ratio CHI/uChl being-1 3. 

Whereas the biosynthesis of chlorophylls a and b in higher plants has been described in detail, the synthesis and regulation of related substances found in less well-known algal groups and lower plants are largely unknown and will be areas of scientific interest in the future. Different and new types of chlorophylls and related substances have been reported and little is known about their possible biological... 

Hortensteiner, S. et ah. The key step in chlorophyll breakdown in higher plants Cleavage of pheophorbide a macrocycle by a monooxigenase, J. Biol. Chem., 273, 15335, 1998. 

Hortensteiner, S., Chlorophyll breakdown in higher plants and algae. Cell. Mol. Life... 

Krautler, B., UnraveUing chlorophyll catabolism in higher plants, Biochem. Soc. Trans., 30, 625, 2002. 

Carotenoids are also present in animal products such as eggs, lobsters, greyflsh, and various types of hsh. In higher plants, they occur in photosynthetic tissues and choloroplasts where their color is masked by that of the more predominant green chlorophyll. The best known are P-carotene and lycopene but others are also used as food colorants a-carotene, y-carotene, bixin, norbixin, capsanthin, lycopene, and P-apo-8 -carotenal, the ethyl ester of P-apo-8-carotenic acid. These are Upid-soluble compounds, but the chemical industry manufactures water-dispersible preparations by formulating coUoid suspensions by emulsifying the carotenoids or by dispersing them in appropriate colloids. ... 

However, this accumulation has not been unequivocally proven. The recent identihcation of urobilinogenoidic linear tetrapyrroles in extracts from primary leaves of barley indicated that further degradation of the v-NCC 1 can take place. While the monoxygenation of pheophorbide a in the earlier phases of chlorophyll breakdown in higher plants appears to be a remarkably stringent entry point, the rather diverse structures of NCCs may indicate that the later phases of the detoxi-hcation process follow less strictly regulated pathways." ... 

Figure E9.1 illustrates the photosynthetic process as it occurs in higher plants. This is called noncyclic photophosphorylation to distinguish it from cyclic photophosphorylation in photosynthetic bacteria. Cyclic photophosphorylation requires only photosystem I and a second series of electron carriers to return electrons to the electron-deficient chlorophyll. The dashed line in Figure E9.1 indicates the flow of electrons in cyclic photophosphorylation. ATP is produced during the cyclic process just as in the noncyclic process, but NADPH is not.

The starting point of chlorophyll is the reaction between two molecules of S-aminolevulinic acid. S-Aminolevulinic acid in higher plants is produced from glutamic acid. 

LOCATION AND ORGANISATION OF THE CHLOROPHYLL-PROTEINS OF PHOTOSYNTHETIC REACTION CENTRES IN HIGHER PLANTS... 

Shiozawa, J.A., Alberte, R.S. and Thomber, J.P. 1974. The P700-chlorophyll a-protein. Isolation and some characteristics of the complex in higher plants. Arch. Biochem. Biophys., 165. 388-397. 

Like chlorophyll, plastoquinone A has a nonpolar terpenoid or isoprenoid tail, which can stabilize the molecule at the proper location in the lamellar membranes of chloroplasts via hydrophobic reactions with other membrane components. When donating or accepting electrons, plastoquinones have characteristic absorption changes in the UV near 250 to 260, 290, and 320 nm that can be monitored to study their electron transfer reactions. (Plastoquinone refers to a quinone found in a plastid such as a chloroplast these quinones have various numbers of isoprenoid residues, such as nine for plastoquinone A, the most common plastoquinone in higher plants see above.) The plastoquinones involved in photosynthetic electron transport are divided into two categories (1) the two plastoquinones that rapidly receive single electrons from Peso (Qa and Qb) and (2) a mobile group or pool of about 10 plastoquinones that subsequently receives two electrons (plus two H+ s) from QB (all of these quinones occur in the lamellar membranes see Table 5-3). From the plastoquinone pool, electrons move to the cytochrome b f complex. 

What organelle in higher plant cells contains chlorophyll ... 

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