Fluorescence of Tryptophan in Keratin

Smith, Gerald J.; Thorpe, M. R.; Melhuish, W. H.; Beddard, Godfrey S.

doi:10.1111/j.1751-1097.1980.tb04047.x

Cited by 12 publications

(7 citation statements)

References 18 publications

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“…30 The effect of such photosensitisation is highlighted by the well-documented fluorescence quenching of phenylalanine and tyrosine by tryptophan, suggesting energy transfer to tryptophan from spatially close aromatic residues in wool. 25,26,31 Another observation from analysis of the digest fragments is that many of the tryptophan-derived chromophoric residues identified in this study were not true tryptically-derived peptides with arginine-or lysine at the Nterminus. Photocleavage of peptide chains as a consequence of protein irradiation is well documented.…”

Section: Tryptophan-derived Photomodificationsmentioning

confidence: 80%

Characterisation of photo-oxidation products within photoyellowed wool proteins: tryptophan and tyrosine derived chromophores

Dyer¹,

Bringans²,

Bryson³

2006

Photochem Photobiol Sci

102

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Understanding the photodegradation of complex protein systems represents a significant goal in protein science. The photo-oxidation and resultant photoyellowing of wool in sunlight is a severe impediment to its marketability. However, although some photomodifications have been found in irradiated model amino acid systems, direct identification of the chromophoric photoproducts responsible for photoyellowing in irradiated wool itself has proved elusive. We here describe the direct characterisation and location of yellow chromophores and related photomodifications within the proteins of photoyellowed wool fabric, utilising a quasi-proteomic approach. In total, eight distinct photoproducts were characterised. Of these, five were derived from tryptophan; namely hydroxytryptophan, N-formylkynurenine, kynurenine, residues consistent with the dehydration of kynurenine, and hydroxykynurenine, while three were derived from tyrosine; namely dihydroxyphenylalanine, dityrosine, and a cross-linked residue consistent with a hydroxylated dityrosine residue. Fourteen modified peptide sequences were identified and the positions of modification for thirteen of these were located within the primary structure of known wool proteins. The nature of the photoproducts characterised offer valuable insight into the reaction pathways followed in the UV-induced photoyellowing of wool proteins.

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Section: Tryptophan-derived Photomodificationsmentioning

confidence: 80%

Characterisation of photo-oxidation products within photoyellowed wool proteins: tryptophan and tyrosine derived chromophores

Dyer¹,

Bringans²,

Bryson³

2006

Photochem Photobiol Sci

102

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“…Such residues, in particular tyrosine, are involved in the process of energy transfer from UV irradiation to tryptophan. UV irradiated tyrosine and phenylalanine have suppressed fluorescence in the presence of tryptophan, resulting from such internal energy transfer [30][31][32]. This energy transfer from aromatic moieties, including FWAs, in close proximity to tryptophan, may facilitate the photo-oxidative process.…”

Section: The Photochemistry Of Kynureninementioning

confidence: 99%

Kynurenine Located within Keratin Proteins Isolated from Photoyellowed Wool Fabric

Bringans¹,

Dyer²,

Plowman³

et al. 2006

Textile Research Journal

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This paper describes the identification of the yellow chromophore-containing residue kynurenine within photoyellowed wool. Photoyellowed Merino wool fabric was tryptically digested and the resultant peptides were separated by high-performance liquid chromatography. Peaks with absorbance at 400 nm were collected and analyzed by tandem quadrupole time-of-flight mass spec-trometry. Kynurenine was identified as a yellow chromophore in two peptide sequences characteristic of Type 1 intermediate filament and high glycine-tyrosine wool proteins. To our knowledge this is the first conclusive evidence confirming the identity of photoyellowed products and their location within the primary structure of wool proteins. A number of non-yellow modifications were identified in the course of this study and taken together with the identification of kynurenine modifications, these results support the current mechanistic theory of the radical oxidative process occurring during photoyellowing.

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“…In addition, several studies have utilized fluorescence as a clinical assessment technique to determine skin ageing, proliferation, treatment efficacy and to characterize carcinomas [8][9][10][11][12][13]. Studies were also completed with keratin fibresinitially wool, which is morphologically and biochemically very similar to hair keratin [14][15][16][17]. Later, such experimental approaches were extended to human hair -in particular to monitor Trp, an endogenous molecular probe, as an indicator of overall hair health [18,19].…”

Section: Introductionmentioning

confidence: 99%

Spectrofluorescence of skin and hair

McMullen

Chen

Moore

2012

Intern J of Cosmetic Sci

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There are numerous chromophores present throughout the strata of human skin, which present many challenges and opportunities to probe molecular events. Fluorescence spectroscopy is principally employed to identify important biochemical components of the skin including endogenous tryptophan, tyrosine, pepsin-digestible collagen cross-links, collagenase-digestible collagen cross-links, NADH, etc. Over the last 15 years, many advances in instrument technology have been introduced allowing for much faster data acquisition with spectrofluorometers. As a result, a series of spectrofluorescence emission scans can be generated for a range of excitation wavelengths, or vice versa (excitation scans for a range of emission wavelengths), quickly to generate excitation-emission matrices. In this work, we constructed an endogenous fingerprint of fluorescent compounds present in skin, hair and nail tissues by employing a range of excitation wavelengths from 270 to 450 nm with a resolution of 2 nm. As a result, we generated surface plots of fluorescence emission as a function of excitation and emission wavelengths. From these data, we identified the predominant fluorescent chromophores in each tissue. We examined several sources of skin including in vivo human and ex vivo pig, sheep, goat and cow skin. We also analysed various types of mature hair characterized by the degree of melanin content. These analyses provided us with a fundamental understanding of the effects of melanin distribution in hair fibres and aided with the identification of fluorophores present in hair.

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Fluorescence of Tryptophan in Keratin

Cited by 12 publications

References 18 publications

Characterisation of photo-oxidation products within photoyellowed wool proteins: tryptophan and tyrosine derived chromophores

Characterisation of photo-oxidation products within photoyellowed wool proteins: tryptophan and tyrosine derived chromophores

Kynurenine Located within Keratin Proteins Isolated from Photoyellowed Wool Fabric

Spectrofluorescence of skin and hair

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