Results 131 to 140 of about 2,749 (174)

Spectrophotometric Characterization of Eumelanin and Pheomelanin in Hair

Pigment Cell Research, 1996
Mammalian melanins exist in two chemically distinct forms: the brown to black eumelanins and the yellow to reddish‐brown pheomelanins. They can be quantified by HPLC analysis of pyrrole‐2,3,5‐tricarboxylic acid (PTCA) and aminohydroxyphenylalanine (AHP).
H, Ozeki, S, Ito, K, Wakamatsu, A J, Thody   +3 more
openaire   +4 more sources

Pheomelanin in fish?

Pigment Cell & Melanoma Research, 2015
1 Department of Molecular Biology, Max Planck Institute for Developmental Biology, T€ ubingen, Germany 2 Guest Group Evolutionary Genomics, Max Planck Institute for Evolutionary Biology, Pl€ on, Germany 3 L€ ubeck Institute of Experimental Dermatology, University of L€ ubeck, L€ ubeck, Germany 4 Department of Physiological Chemistry, Biocenter ...
Kottler, V., Künstner, A., Schartl, M.
openaire   +4 more sources

Selenomelanin: An Abiotic Selenium Analogue of Pheomelanin

Journal of the American Chemical Society, 2020
Melanins are a family of heterogeneous biopolymers found ubiquitously across plant, animal, bacterial, and fungal kingdoms where they act variously as pigments and as radiation protection agents. There exist five multifunctional yet structurally and biosynthetically incompletely understood varieties of melanin: eumelanin, neuromelanin, pyomelanin ...
Wei Cao, Naneki C. McCallum, Qing Zhe Ni, Weiyao Li, Hannah Boyce, Haochuan Mao, Xuhao Zhou, Hao Sun, Matthew P. Thompson, Claudia Battistella, Michael R. Wasielewski, Ali Dhinojwala, Matthew D. Shawkey, Michael D. Burkart, Zheng Wang, Nathan C. Gianneschi   +15 more
openaire   +2 more sources

Analysis and Quantification of Pheomelanins by Radioimmunoassay

Pigment Cell Research, 1988
An antiserum against α‐amino‐(4‐hydroxy‐6‐benzothiazolyl)propionic acid (AHBP), a major product obtained after hydriodic acid hydrolysis of pheomelanin, was raised in rabbits immunized with AHBP coupled to bovine serum albumin (BSA). The antiserum was used to develop a radioimmunoassay (RIA) to AHBP. The limit of detection of the RIA is 0.1 ng of AHBP.
A B, Ahene, M R, Chedekel, W H, Koch, W, Maldonado   +3 more
openaire   +2 more sources

The “Benzothiazine” Chromophore of Pheomelanins: A Reassessment^†

Photochemistry and Photobiology, 2007
AbstractThe characteristic absorption and photochemical properties of pheomelanins are generally attributed to “benzothiazine” structural units derived biogenetically from 5‐S‐cysteinyldopa. This notion, however, conveys little or no information about the structural chromophores responsible for the photoreactivity of pheomelanins.
NAPOLITANO, ALESSANDRA, DE LUCIA, MARIA, PANZELLA, LUCIA, D'ISCHIA, MARCO   +3 more
openaire   +4 more sources

PHOTOCHEMISTRY OF BENZOTHIAZOLE MODELS OF PHEOMELANIN

Photochemistry and Photobiology, 1984
Abstract— The photochemistry of several 4‐hydroxy‐ and 4‐methoxybenzothiazoles has been investigated by laser flash photolysis. In aqueous solutions of pH3–12, the 4‐hydroxybenzothiazole chromophore undergoes monophotonic photoionization to afford e‐aq with quantum yields on the order of 0.06; no evidence for triplet species was obtained.
CHRIS LAMBERT, ROY S. SINCLAIR, T. GEORGE TRUSCOTT, EDWARD J. LAND, R. MILES, CHUNG‐TSING LIU   +5 more
openaire   +1 more source

PHEOMELANIN PHOTOCHEMISTRY. PHOTOLYSIS OF MODEL COMPOUNDS

Photochemistry and Photobiology, 1982
Abstract Two pheomelanin model compounds were prepared and their photochemistries examined. Upon irradiation, an oxygen‐mediated photopolymerization reaction was observed. The photopolymers obtained were characterized by their apparent molecular weights, UV and fluorescence spectra.
C T, Liu, M R, Chedekel
openaire   +2 more sources

Pheomelanin as a Binding Site for Drugs and Chemicals

Pigment Cell Research, 1999
Certain drugs and chemicals, such as chloroquine, chlorpromazine, and 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP), are bound to melanin and retained in pigment cells for long periods. This specific retention in pigmented tissues can cause adverse effects in the skin, eye, inner ear, and pigmented nerve cells of the substantia nigra of the brain.
U, Mårs, B S, Larsson
openaire   +2 more sources

UVA, Pheomelanin and the Carcinogenesis of Melanoma

Pigment Cell Research, 2000
Cloudman S91 mouse melanoma cells vary in constitutive and inducible melanin levels. Survival, mutation induction and DNA damage were quantitated after exposure to UVB, UVA and FS20 lamps. Assuming that the observed differences are related to melanin, induced pigment is photo‐protective for survival and mutation after UVB and FS20 exposure, and is ...
HELENE Z. HILL, GEORGE J. HILL
openaire   +1 more source

Vibrational characterization of pheomelanin and trichochrome F by Raman spectroscopy

Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy, 2013
We characterize for the first time the vibrational state of natural pheomelanin using Raman spectroscopy and model pigment synthesized from 5-S-cysteinyldopa. The shape of the Raman spectrum was very different from that of eumelanin. Four Raman bands were visible in the 500-2000 cm(-1) wavenumber region about 500, 1150, 1490 and 2000 cm(-1), which we ...
Alberto Jorge, Ismael Galvan, Kazumasa Wakamatsu   +2 more
exaly   +3 more sources