Cross-polarization/magic-angle-spinning nuclear magnetic resonance in selectively 13C-labeled synthetic eumelanins

Reinheimer, Pierre; Hirschinger, Jérôme; Granger, Pierre; Breton, Philippe; Lagrange, Alain; Gilard, Patrick; Lefebvre, Marc; Goetz, N.

doi:10.1016/s0304-4165(99)00127-0

Cited by 11 publications

(17 citation statements)

References 41 publications

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“…The integrity of the melanosomes is well preserved for those extracted from black hair. The surfaces of the melanosomes are fairly smooth and the morphology resembles the intact melanosomes imaged by transmission electron microscopy of thin sections of human hair (40). A small number of black-hair melanosomes show material adhering to their surface (arrows in Fig.…”

Section: Morphology Analysismentioning

confidence: 81%

“…Before Fourier transformation, the time-domain signals were apodized using a line broadening of 200 Hz. Short CP contact time (40 ls) experiments were also carried out to separate the protonated carbon atoms from the nonprotonated carbon atoms (40,41). IR samples were prepared by mixing dried melanosomes with KBr in a mass ratio of ;1:1000 and pressed by IR die (McCarthy Scientific Co, Fallbrook, CA) resulting in transparent pellets.…”

Section: Methodsmentioning

confidence: 99%

“…This technique is of special interest for the structural studies of melanin because melanin is not soluble in any solvent without disrupting its structure (40,(49)(50)(51). There was a recent report of the 13 C solid-state NMR studies on the natural melanins (41).…”

Section: Solid-state Cp/mas 13 C Nmrmentioning

confidence: 99%

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Comparison of Structural and Chemical Properties of Black and Red Human Hair Melanosomes¶

Liu

Hong

Wakamatsu

et al. 2005

Photochem Photobiol

173

133

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Melanosomes in black and red human hair are isolated and characterized by various chemical and physical techniques. Different yields of 4-amino-hydroxyphenolanaline by HI hydrolysis (a marker for pheomelanin) and pyrrole-2,3,5-tricarboxylic acid by KMnO(4)/H(+) oxidation (a marker for eumelanin) indicate that the melanosomes in black hair are eumelanosomes, whereas those in red hair are mainly pheomelanosomes. Atomic force microscopy reveals that eumelanosomes and pheomelanosomes have ellipsoidal and spherical shapes, respectively. Eumelanosomes maintain structural integrity upon extraction from the keratin matrix, whereas pheomelanosomes tend to fall apart. The black-hair eumelanosomes have an average of 14.6 +/- 0.5% amino acids content, which is attributed to the internal proteins entrapped in the melanosomes granules. The red-hair melanosomes contain more than 44% of amino acid content even after extensive proteolytic digestion. This high content of amino acids and the poorly reserved integrity of red-hair melanosomes suggest that some proteins are possibly covalently bonded with the melanin constituents in addition to those that are entrapped inside the melanin species. Soluene solubilization assay indicates the absorbance of melanin per gram of sample, adjusted for the amino acid content, is a factor of 2.9 greater for the black-hair melanosomes than the red-hair melanosomes. Metal analysis reveals significant amounts of diverse heavy metal ions bound to the two types of melanosomes. The amount of Cu(II) and Zn(II) are similar but Fe(III) content is four times higher in the red-hair melanosomes. (13)C solid-state nuclear magnetic resonance spectra and infrared spectra are presented and are shown to be powerful techniques for discerning differences in the amino acid contents, the 5,6-dihydroxyindole-2-carboxylic acid:5,6-dihydroxyindole ratio, and the degree of cross-linking in the pigment. Excellent agreement is observed between these spectral results and the chemical degradation data.

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Section: Morphology Analysismentioning

confidence: 81%

Section: Methodsmentioning

confidence: 99%

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Comparison of Structural and Chemical Properties of Black and Red Human Hair Melanosomes¶

Liu

Hong

Wakamatsu

et al. 2005

Photochem Photobiol

173

133

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“…The product then undergoes radical polymerization to yield the black insoluble eumelanin. The relative amounts of DHICA and DHI vary between species (Reinheimer et al 1999). When cysteine is present, dopaquinone reacts with it to form a variety of cysteinyl-dopa adducts, resulting in benzothiazine intermediates that oligomerize to form pheomelanin.…”

Section: Introductionmentioning

confidence: 99%

The fungus Gliocephalotrichum simplex as a source of abundant, extracellular melanin for biotechnological applications

Jalmi¹,

Bodke²,

Wahidullah

et al. 2011

World J Microbiol Biotechnol

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Melanins are commonly produced by bacteria, fungi, plants and animals, where they play a role in many biological functions. They protect organisms against UV and ionizing radiations. Their potential applications in biotechnological industries such as cosmetics and paints, where UV protection is required, are hampered by the lack of suitable organisms or methods to produce them abundantly. We report here the production of high amounts of extracellular melanin by the fungus Gliocephalotrichum simplex in cultures supplemented with tyrosine. Their typical UV-absorbance, as well as i.r., (13)C solid-state and (1)H NMR spectra indicated that the melanin is a eumelanin, being a copolymer of dihydroxyindole carboxylic acid and dihydroxyindole, associated with some carbohydrates and proteinaceous matter. Optimal culture conditions established by a Plackett-Burman experiment, followed by a full factorial experiment based on tyrosine and peptone yielded a maximum of up to 6.6 g melanin l(-1). The high yields of extracellular melanin from G. simplex enables its use in biotechnology.

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“…Numerous analytical studies for the elucidation of melanin structures have included solid‐state nuclear magnetic resonance (NMR) spectroscopic examinations of fungal melanins (4), melanoma, synthetic DOPA and Sepia melanins (5–7), eumelanins (8–10), and human mesencephalic neuromelanins (11). X‐ray studies have also been applied to the structures of Sepia melanin, L ‐DOPA, and tyrosine synthetic melanin (12), and eumelanin (13).…”

Section: Introductionmentioning

confidence: 99%

¹H NMR Spectroscopic Characterization of Solutions of Sepia Melanin, Sepia Melanin Free Acid and Human Hair Melanin

Katritzky

Akhmedov

Denisenko

et al. 2002

Pigment Cell Research

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Cross-polarization/magic-angle-spinning nuclear magnetic resonance in selectively 13C-labeled synthetic eumelanins

Cited by 11 publications

References 41 publications

Comparison of Structural and Chemical Properties of Black and Red Human Hair Melanosomes¶

Comparison of Structural and Chemical Properties of Black and Red Human Hair Melanosomes¶

The fungus Gliocephalotrichum simplex as a source of abundant, extracellular melanin for biotechnological applications

¹H NMR Spectroscopic Characterization of Solutions of Sepia Melanin, Sepia Melanin Free Acid and Human Hair Melanin

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Cross-polarization/magic-angle-spinning nuclear magnetic resonance in selectively 13C-labeled synthetic eumelanins

Cited by 11 publications

References 41 publications

Comparison of Structural and Chemical Properties of Black and Red Human Hair Melanosomes¶

Comparison of Structural and Chemical Properties of Black and Red Human Hair Melanosomes¶

The fungus Gliocephalotrichum simplex as a source of abundant, extracellular melanin for biotechnological applications

1H NMR Spectroscopic Characterization of Solutions of Sepia Melanin, Sepia Melanin Free Acid and Human Hair Melanin

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¹H NMR Spectroscopic Characterization of Solutions of Sepia Melanin, Sepia Melanin Free Acid and Human Hair Melanin