Reduction of the Formyl Group of Zinc Pheophorbide b in vitro and in vivo: a Model for the Chlorophyll b to a Transformation

Scheumann, Verena; Helfrich, Michael; Schoch, Siegrid; Rüdiger, Wolfhart

doi:10.1515/znc-1996-3-409

Cited by 27 publications

(24 citation statements)

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“…The yield was 70%. Zinc 7'-hydroxypheophytin a and zinc 7'-hydroxypheophorbide a were prepared according to Scheumann et al (1996).…”

Section: Methodsmentioning

confidence: 99%

“…The conclusion that reduction of the formyl group occurs only after esterification can be questioned because application of esterified Chl b proved to be unsuccessful (It0 et al, 1994). Infiltration of zinc pheophorbide b and of zinc 7'-hydroxypheophorbide a into segments of etiolated oat leaves resulted in formation of zinc pheophytin a indicating that leaf tissue cannot only perform the first step but also the second step of the b-to-a-transformation (Scheumann et al, 1996). Since no 7'-hydroxy compound was accumulated even in the presence of an excess of zinc pheophorbide b, we have to conclude that the second reduction step is faster than the first one, i.e.…”

Section: R / Cooch"mentioning

confidence: 99%

“…HPLC. Analysis of pigments was performed with an HPLC unit consisting of a gradient former (M 250 B) and high precision pump (model 300C, both from Gynkotek) connected to a column (250 mmx4.6 mm) filled with reverse-phase material (Rosil C-18, size 5 pm) at a flow rate of 1.5 pl/min (Scheumann et al, 1996). The solvent system for unesterified pigments started with 50% acetone/water, adjusted to pH 3.5 with acetic acid.…”

Section: Enzymatic Reduction All Manipulations With Etioplastsmentioning

confidence: 99%

“…However, we demonstrated recently that this reaction can be achieved in a chemical reaction provided that a central metal (e.g. zinc) is present (Scheumann et al, 1996); the carbony1 group of the isocyclic ring remained intact. An intermediate of the chemical reduction is the 7l-hydroxy compound (Scheme 1).…”

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confidence: 99%

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Substrate Specificity of Chlorophyll(ide) b Reductase in Etioplasts of Barley (Hordeurn Vulgare L.)

Scheumann

Itô

Tanaka

et al. 1996

European Journal of Biochemistry

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Enzyme activity of chlorophyll(ide) b reductase is present in etioplasts. Recently the conversion of chlorophyllide b to chlorophyll a via 7'-hydroxychlorophyll a was demonstrated in barley etioplasts. We used zinc pheophorbide b for a detailed investigation of the reduction of the 7-formyl group to the 7l-hydroxy compound in intact barley etioplasts. The reaction proceeded likewise before esterification and after esterification with phytyl diphosphate. The metal-free pheophorbide b, that is not accepted by chlorophyll synthase for esterification, is reduced to 71-hydroxypheophorbide a to a small extent. The zinc (13'S)-pheophorbide b is at least equally well accepted for reduction as the epimer with the 13'R configuration of natural chlorophyll b. The reaction requires NADPH or NADH, although the latter is less effective. ATP is not required for the first step to the 7I-hydroxy compound. The significance of chlorophyll b reduction for acclimation from shade to sun leaves and for chlorophyll degradation is discussed.

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“…The yield was 70%. Zinc 7'-hydroxypheophytin a and zinc 7'-hydroxypheophorbide a were prepared according to Scheumann et al (1996).…”

Section: Methodsmentioning

confidence: 99%

Section: R / Cooch"mentioning

confidence: 99%

Section: Enzymatic Reduction All Manipulations With Etioplastsmentioning

confidence: 99%

mentioning

confidence: 99%

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Substrate Specificity of Chlorophyll(ide) b Reductase in Etioplasts of Barley (Hordeurn Vulgare L.)

Scheumann

Itô

Tanaka

et al. 1996

European Journal of Biochemistry

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“…First the 7 1 -hydroxy derivative 49 can be detected from which an intermediate geminal diol forms and spontaneously loses water during the formation of chlorophyllide b 50 [151,152]. This pathway is also reversible using the chlorophyllide b reductase and 7-hydroxymethyl chlorophyll a reductase which allows a conversion of Chl b into Chl a in what is known as the "chlorophyll cycle" [153][154][155]. …”

Section: Chlorophylls a And Bmentioning

confidence: 99%

Chlorophylls, Symmetry, Chirality, and Photosynthesis

et al. 2014

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Chlorophylls are a fundamental class of tetrapyrroles and function as the central reaction center, accessory and photoprotective pigments in photosynthesis. Their unique individual photochemical properties are a consequence of the tetrapyrrole macrocycle, the structural chemistry and coordination behavior of the phytochlorin system, and specific substituent pattern. They achieve their full potential in solar energy conversion by working in concert in highly complex, supramolecular structures such as the reaction centers and light-harvesting complexes of photobiology. The biochemical function of these structures depends on the controlled interplay of structural and functional principles of the apoprotein and pigment cofactors. Chlorophylls and bacteriochlorophylls are optically active molecules with several chiral centers, which are necessary for their natural biological function and the assembly of their supramolecular complexes. However, in many cases the exact role of chromophore stereochemistry in the biological context is unknown. This review gives an overview of chlorophyll research in terms of basic function, biosynthesis and their functional and structural role in photosynthesis. It highlights aspects of chirality and symmetry of chlorophylls to elicit further interest in their role in nature.

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Reductive Aminations of Carbonyl Compounds with Borohydride and Borane Reducing Agents

2002

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Reductive amination is an important tool for synthetic organic chemists in the construction of carbon‐nitrogen bonds. This reaction, also termed reductive alkylation, involves condensation of an aldehyde or ketone with an amine in the presence of a reducing agent. A wide variety of substrates can be used including aliphatic and aromatic aldehydes and ketones, and even benzophenones. A range of amines from ammonia to aromatic amines, including those with electron‐withdrawing substituents, can be employed. For particularly sluggish reactions, such as those involving weakly electrophilic carbonyl groups, poorly nucleophilic amines, or sterically congested reactive centers, additives such as molecular sieves or Lewis acids are often useful. This chapter focuses on those conditions in which the carbonyl component, amine, and reducing reagent react in the same vessel. This review is restricted to reductive aminations using borohydride and borane reducing agents. This chapter concentrates on reductive amination chemistry mediated by borohydride and other boron‐containing reducing agents from 1971, the year when sodium cyanoborohydride was introduced, through the middle of 1999. In addition to reductive aminations of aldehyde and ketone substrates, reactions of related structures including acetals, aminals, ketals, carboxylic acids, nitriles, and dicarbonyls that form a nitrogen‐containing ring are reviewed. Intramolecular processes in which the substrate contains both the carbonyl and amine moieties are described. The intramolecular variant is a useful method for preparing cyclic amines. All of the various boron‐containing hydride sources in reductive aminations, including labeled metal hydrides, are reviewed. Instances of reductive aminations that failed are described. Applications of this method to a solid support in parallel synthesis in combinatorial chemistry as well as reductive aminations that proceed in tandem with a second reaction such as reductive lactamizations are discussed.

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Reduction of the Formyl Group of Zinc Pheophorbide b in vitro and in vivo: a Model for the Chlorophyll b to a Transformation

Cited by 27 publications

References 0 publications

Substrate Specificity of Chlorophyll(ide) b Reductase in Etioplasts of Barley (Hordeurn Vulgare L.)

Substrate Specificity of Chlorophyll(ide) b Reductase in Etioplasts of Barley (Hordeurn Vulgare L.)

Chlorophylls, Symmetry, Chirality, and Photosynthesis

Reductive Aminations of Carbonyl Compounds with Borohydride and Borane Reducing Agents

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