6 Lignin-protein complex in cell walls of Pinus elliottii: Amino acid constituents

Whitmore, F. W.

doi:10.1016/s0031-9422(00)95258-0

Cited by 61 publications

(33 citation statements)

References 11 publications

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“…Furthermore, the lignin appeared to be covalently bound to a cell wall protein containing hydroxyproline. Whitmore suggested that polymerizing lignin was covalently coupled to cell wall structural proteins and that the occurrence of lignoproteins was consistent with the fungi degrading the lignin not only to access the cellulose but also the protein-bound nitrogen [101]. Tyrosine residues were implicated in the covalent crosslinking of horseradish peroxidase to DHPs of coniferyl alcohol catalyzed by the enzyme itself in the presence of H 2 O 2 .…”

Section: Lignin-protein Interactions?mentioning

confidence: 89%

Supramolecular Self-Assembled Chaos: Polyphenolic Lignin’s Barrier to Cost-Effective Lignocellulosic Biofuels

et al. 2010

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Phenylpropanoid metabolism yields a mixture of monolignols that undergo chaotic, non-enzymatic reactions such as free radical polymerization and spontaneous selfassembly in order to form the polyphenolic lignin which is a barrier to cost-effective lignocellulosic biofuels. Post-synthesis lignin integration into the plant cell wall is unclear, including how the hydrophobic lignin incorporates into the wall in an initially hydrophilic milieu. Self-assembly, self-organization and aggregation give rise to a complex, 3D network of lignin that displays randomly branched topology and fractal properties. Attempts at isolating lignin, analogous to archaeology, are instantly destructive and nonrepresentative of in planta. Lack of plant ligninases or enzymes that hydrolyze specific bonds in lignin-carbohydrate complexes (LCCs) also frustrate a better grasp of lignin. Supramolecular self-assembly, nano-mechanical properties of lignin-lignin, ligninpolysaccharide interactions and association-dissociation kinetics affect biomass deconstruction and thereby cost-effective biofuels production. OPEN ACCESSMolecules 2010, 15 8642

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Section: Lignin-protein Interactions?mentioning

confidence: 89%

Supramolecular Self-Assembled Chaos: Polyphenolic Lignin’s Barrier to Cost-Effective Lignocellulosic Biofuels

et al. 2010

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“…Indeed, it has been commonly hypothesized that the localization of lignin is dependent on specific interactions of its precursors or enzymes involved in its polymerization with particular polysaccharides or proteins in the wall matrix (Hepler and Fosket, 1970;Hepler et a/., 1972;Keller et a/., 1989;O'Brien, 1974;Roberts et a/., 1985;Yamamoto et al, 1989;Ye and Varner, 1991). This hypothesis is supported by evidence that: (i) the polymerization of a lignin-like molecule can occur in vitro in the presence of eugenol, hydrogen peroxide, peroxidase, and a polysaccharide matrix (Siegel, 1962, as quoted in Hepler andFosket, 1970); (ii) lignin or its precursors can become covalently bound to polysaccharides and proteins that are commonly found in cell walls Wardrop, 1981;Whitmore, 1982;Yamamoto et al, 1989). However, direct experimental evidence showing that lignin localization depends on the presence of particular cell wall polymers was not previously available until this study.…”

Section: Introductionmentioning

confidence: 93%

“…Whether or not bonding sites for the molecules that directly mediate lignin localization are or remain available would be determined by the type of wall polymers that were initially present. For example, the interaction of lignin precursors with hydroxyproline relies on the presence of unsubstituted hydroxyls in the amino acid, but these are extensively blocked by glycosidic bonds in some tissues (Whitmore, 1982). Therefore, the pre-existing cellulose in the primary wall of differentiating TEs might not be able to mediate the localization of lignin because of its prior interaction with matrix materials specific to primary wall.…”

Section: Mechanisms By Which Localization Of Cellulose Might Mediate mentioning

confidence: 99%

Dispersed lignin in tracheary elements treated with cellulose synthesis inhibitors provides evidence that molecules of the secondary cell wall mediate wall patterning

et al. 1992

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SummaryMesophyll cells of Zinnia elegans var. Envy that had been induced to differentiate into tracheary elements (TEs) in suspension culture were treated with the cellulose synthesis inhibitor 2,6-dichlorobenzonitrile (DCB). The deposition of cellulose into the patterned secondary cell wall thickenings typical of TEs was inhibited as demonstrated by reduced incorporation of [14C]glucose into acetichitric insoluble material and absence of cellulose detectable by fluorescence after staining with Tinopal LPW, polarization optics, or labeling with a specific cellulase. Respiration as indicated by release of I4CO2 was inhibited to a much lesser extent, supporting a selective mechanism of action of DCB on the cellulose biosynthetic pathway. Patterned secondary cell wall thickenings were deposited in DCB-treated TEs, but these were smaller and less regularly shaped than those of control TEs. These cellulose-depleted thickenings lacked another abundant component of normal thickenings, the hemicellulose xylan, as indicated by absence of labeling with a specific xylanase or an antibody to xylan. DCBtreated TEs also showed dispersed lignin after staining with phloroglucinol, whereas control TEs contained lignin specifically localized to the secondary cell wall thickenings. Isoxaben, another recently described inhibitor of synthesis of acetichitric insoluble cell wall material (putatively cellulose), caused the same absence of detectable cellulose and xylan in the thickenings and dispersed lignin. These data suggest that: (i) the localization of lignin is ultimately dependent on the localization of cellulose; (ii) normal patterned wall assembly in TEs occurs in a self-perpetuating cascade in which some molecules of the secondary cell wall mediate patterning of others.

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“…Com a exceção das LBrAc provenientes das madeiras, as demais apresentaram apreciáveis teores de proteína (PB); embora não tenha sido estabelecida prova química, existe proposta de que proteínas são covalentemente ligadas à molécula de lignina (WHITMORE, 1982). No presente trabalho, estes valores ficaram entre 4,9 (aveia madura) e 21,4% (colonião jovem), sendo que as plantas jovens exibiram teores mais elevados que as plantas maduras.…”

Section: Resultsunclassified

Extração da lignina e emprego da mesma em curvas de calibração para a mensuração da lignina em produtos vegetais

et al. 2000

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RESUMO -O objetivo deste experimento foi a extração da lignina e seu uso nas curvas de calibração para determinar a concentração de lignina em produtos vegetais. Dentre os métodos analíticos utilizados para a mensuração da lignina, pode-se mencionar o método "lignina solúvel em brometo de acetila -LSBA", no qual a lignina é solubilizada em uma solução de brometo de acetila a 25% em ácido acético glacial e, depois, lida no comprimento de onda a 280 nm. Entretanto, todo método espectrofotométrico requer o emprego de um padrão de referência confiável; neste experimento utilizou-se como padrão de referência a lignina da planta forrageira extraída com o emprego do próprio brometo de acetila. Quantificou-se a lignina presente em quatro amostras de forrageiras, em dois estádios de maturidade e, ainda, em duas amostras de madeiras, comparando-se os dados com outros dois métodos de determinação da lignina (lignina em detergente ácido -LDA e lignina permanganato de potássio -LPer). Os três métodos não foram concordantes entre si, sendo que, para praticamente todas as amostras, o método da LSBA mostrou valores mais elevados que os outros dois métodos. Para cada amostra analisada, foram confeccionados uma curva-padrão e um espectrograma na faixa de comprimento de luz de 240 a 320 nm. A análise dessas curvas e dos espectrogramas indicou diferenças qualitativas entre as amostras, em função não apenas da espécie botânica, mas também do estádio de maturidade da planta.Palavras-chave: análise química, espectrofotometria, lignina, plantas forrageiras Lignin Extraction and its Performance in Calibration Curves to Determine Lignin Concentration in PlantsABSTRACT -The objective of this experiment was the extraction of lignin and its use in the calibration curves to determine lignin concentration in vegetable plants. Among the analytical methods for measuring lignin concentration, there is the "acetyl bromide soluble lignin -ABSL" method, were solubilized lignin in 25% solution of acetyl bromide in glacial acetic acid is read at 280 nm. However, any spectrophotometric method requires a reliable standard to which optical density readings are compared; in this experiment, the standard was obtained through extraction with acetyl bromide reagent. Lignin was quantified in four forage samples, at two maturity stages, and also in two wood samples, comparing the obtained data with two other analytical methods for lignin (acid detergent lignin -ADL and potassium permanganate lignin -PerL). The three techniques yielded different values for the same samples; in general, the ABSL method showed higher lignin concentrations than the two other methods. For each sample it was made a standard curve and a 240-320 nm ultraviolet scanning. Analyses of such curves and scannings indicated qualitative differences among samples, not only related to plant species, but also to maturity stage of vegetable samples.Key Words: chemical analysis, forages, lignin, spectrophotometric analysis Rev. bras. zootec., 29(5):1302-1311, 2000Introdução A lignina é um compone...

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6 Lignin-protein complex in cell walls of Pinus elliottii: Amino acid constituents

Cited by 61 publications

References 11 publications

Supramolecular Self-Assembled Chaos: Polyphenolic Lignin’s Barrier to Cost-Effective Lignocellulosic Biofuels

Supramolecular Self-Assembled Chaos: Polyphenolic Lignin’s Barrier to Cost-Effective Lignocellulosic Biofuels

Dispersed lignin in tracheary elements treated with cellulose synthesis inhibitors provides evidence that molecules of the secondary cell wall mediate wall patterning

Extração da lignina e emprego da mesma em curvas de calibração para a mensuração da lignina em produtos vegetais

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