Die Zusammensetzung des Chlorophylls

Stoll, A.; Wiedemann, E.

doi:10.1002/hlca.19330160124

Cited by 32 publications

(13 citation statements)

References 9 publications

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“…In both systems, the absorption bands correlated with the macrocyclic chromophore are optically active, i.e., they exhibit Cotton effects in the ORD spectra. 1,2 Although in hemoproteins the heme Cotton effects are induced by interactions of the achiral chromophore with the chiral protein environment, 550 Annals New York Academy of Sciences observed by Stoll and Wiedemann 7 and was confirmed by Fischer and Stern 8 using a Polarimeter with greater light intensity. Except for the dextrorotatory purpurins, they observed levorotation for a great number of chlorins.…”

Section: Institut Für Organische Chemie Der Tu 33 Braunschweig and Gementioning

confidence: 87%

Stereochemistry and Chiroptic Properties of Pheophorbides and Related Compounds*

Wolf¹,

Scheer²

1973

Annals of the New York Academy of Sciences

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Section: Institut Für Organische Chemie Der Tu 33 Braunschweig and Gementioning

confidence: 87%

Stereochemistry and Chiroptic Properties of Pheophorbides and Related Compounds*

Wolf¹,

Scheer²

1973

Annals of the New York Academy of Sciences

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“…Similarly, in the presence of an excess of simple alcohols, e.g., methanol, the same reactions yield the corresponding transesterified alkyl chlorophyllide a (26) or alkyl pheophorbide a (27). Thus, the propionic acid side chain of the macrocycle may be used as a starting point to construct a linked dimer in the form of a bis(chlorophyllide a) diester of an alkanediol, e.g., ethylene glycol, without altering the functionality in ring V. The structure of this molecule is presented in Fig.…”

Section: Synthetic Aspects Of the Covalentmentioning

confidence: 92%

Covalently linked chlorophyll a dimer: A biomimetic model of special pair chlorophyll

Wasielewski

Studier

Katz

1976

Proc. Natl. Acad. Sci. U.S.A.

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The synthesis of a covalent dimer of chlorophyll a which possesses properties strikingly similar to those exhibited by P700 special pair chlorophyll in vivo is described. The covalent dimer is characterized by several spectroscopic techniques. Hydrogen bonding nucleophiles, such as water, primary alcohols, and primary thiols, are effective in generating a species from solutions of 10 ,sM covalent dimer in hydrophobic solvents which absorbs light near 700 nm. Formation of this in vitro special pair is a rapid, spontaneous process at room temperature. The range of nucleophiles which promote this process suggests that amino acid residues may function in a similar fashion to form P700 in chlorophyll-protein complexes. The photochemical properties of this in vitro special pair mimic those of in vivo P700 species. The 697 nm a sorption of the in vitro special pair undergoes photo-bleaching rapidly in the presence of iodine that results in the production of a cation radical which exhibits an electron spin resonance signal similar to that of oxidized P700 observed in Chlorella vulgaris. Investigations into the molecular organization of chlorophyll in green plants strongly suggest that the chlorophyll molecules act cooperatively in the primary light absorption process of photosynthesis (1-3). The light energy is captured by an extended array of antenna chlorophyll molecules that absorb strongly at 678 nm (4). The electronic excitation produced by the light absorption is transmitted via the antenna chlorophyll to a special pair of chlorophyll molecules absorbing at about 700 nm, that functions as a low energy trap (5). The trapping of the excitation energy by the P700 special pair results in one electron oxidation of the pair to yield the special pair cation radical, and an electron which ultimately furnishes the reducing potential of photosystem 1 (6). There is good evidence from studies in vivo that the species designated P700 is actually a pair of chlorophyll a (Chl a) molecules.In the visible spectra of systems in vivo, P700 undergoes bleaching upon illumination with red light to a greater extent than does P680 (7-10). The subsequent appearance of a photo-induced electron spin resonance signal of about 7 gauss linewidth with g = 2.0025 suggests the formation of P700t (11) Chl a. Two such interactions result in a structure possessing C2 symmetry with an approximate 8.9 A Mg-Mg distance and 3.6 A interplanar separation between the macrocycles. In this model, the carbomethoxy groups are pointed away from the center of the structure and the phytyl tails extend in similar directions from the macrocycles.Spectroscopic evidence indicates that the keto carbonyl group of Chl a is the primary nucleophilic donor moiety and is of principal importance in Chl a aggregation (14-16). This evidence also supports a minor role for the carbomethoxy group as a donor. Nevertheless, Fong has proposed a model (17) for the structure of the special pair based on the coordination of a water molecule to the magnesium of one Chl a molecu...

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“…Wenige Jahre spater erfolgte die Synthese des naturlichen Alliins und seiner drei optisch aktiven Isomeren. (+)-S-Allyl-L-cystein-sulfoxid envies sich als identisch mit dem natiirlichen Alliin [93]. Als medizinisch sehr erfolgreich erwies sich die in den fruhen fiinfziger Jahren begonnene chemische Untersuchung der im Himalaya-Gebiet heimischen Berberidacee Podophyllum emodi, die mit dem nordamerikanischen Podophyllum peltaturn nahe verwandt ist.…”

Section: Fig41unclassified

Chemie der Kohlenhydrate, der Pflanzeninhaltsstoffe und der mikrobiellen Stoffwechselprodukte im Spiegel der Helvetica Chimica Acta 1918–1992

Tamm

1992

Helvetica Chimica Acta

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Die Zusammensetzung des Chlorophylls

Cited by 32 publications

References 9 publications

Stereochemistry and Chiroptic Properties of Pheophorbides and Related Compounds*

Stereochemistry and Chiroptic Properties of Pheophorbides and Related Compounds*

Covalently linked chlorophyll a dimer: A biomimetic model of special pair chlorophyll

Chemie der Kohlenhydrate, der Pflanzeninhaltsstoffe und der mikrobiellen Stoffwechselprodukte im Spiegel der Helvetica Chimica Acta 1918–1992

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