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The Ultraviolet Absorption Coefficient of Melanosomes Decreases with Increasing Pheomelanin Content

dc.contributor.author Peles, Dana N
dc.contributor.author Simon, John D
dc.date.accessioned 2011-06-21T17:26:39Z
dc.date.available 2011-06-21T17:26:39Z
dc.date.issued 2010
dc.identifier.citation Peles,Dana N.;Simon,John D.. 2010. The Ultraviolet Absorption Coefficient of Melanosomes Decreases with Increasing Pheomelanin Content. Journal of Physical Chemistry B 114(29): 9677-9683.
dc.identifier.issn 1520-6106
dc.identifier.uri https://hdl.handle.net/10161/4068
dc.description.abstract Uveal melanosomes from the iridal stroma contain both eumelanin and pheomelanin, the ratio of which varies with iris color. Herein, we report the absorption coefficient at lambda = 244 nm for individual human iridal stroma melanosomes from dark brown and blue-green irides. The melanosomes are nearly identical in size, but differ in the relative concentration composition, ranging from a eumelanin/pheomelanin ratio of 14.8:1 (dark brown) to 1.3:1 (blue-green or hazel). The absorption coefficient of the melanosome decreases as its pheomelanin content increases. The origin of this decrease is attributed to a corresponding decrease in the number of UV-absorbing chromophores, reflecting the different molecular volumes of the monomeric building blocks of the two pigments. In agreement with reported data on synthetic pigments, the absorption coefficient of pheomelanin is found to be slightly larger than that for eumelanin at lambda = 244 nm (by a factor of 1.2). On the basis of the reported optical properties of synthetic models, this result suggests that the absorption of pheomelanin is less than eumelanin at wavelengths of biological relevance (similar to 315-400 nm).
dc.language.iso en_US
dc.publisher AMER CHEMICAL SOC
dc.relation.isversionof 10.1021/jp102603b
dc.subject photoinduced oxygen-consumption
dc.subject chemical-properties
dc.subject human hair
dc.subject transient absorption
dc.subject physical-properties
dc.subject human melanocytes
dc.subject melanin
dc.subject systems
dc.subject ocular melanin
dc.subject quantum yields
dc.subject action spectra
dc.subject chemistry, physical
dc.title The Ultraviolet Absorption Coefficient of Melanosomes Decreases with Increasing Pheomelanin Content
dc.title.alternative
dc.type Other article
dc.description.version Version of Record
duke.date.pubdate 2010-7-29
duke.description.issue 29
duke.description.volume 114
dc.relation.journal Journal of Physical Chemistry B
pubs.begin-page 9677
pubs.end-page 9683


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