Quantification of Naturally Occurring Pyrrole Acids in Melanosomes<sup>†</sup>

Ward, Weslyn C.; Lamb, Erin C.; Gooden, David M.; Chen, Xin; Burinsky, David J.; Simon, John D.

doi:10.1111/j.1751-1097.2008.00328.x

Cited by 15 publications

(8 citation statements)

References 22 publications

(27 reference statements)

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“…Alkaline hydrogen peroxide degradation breaks this copolymer into unique markers ( Fig. 2A), pyrrole-2,3,5-tricarboxylic acid (PTCA), pyrrole-2,3-dicarboxylic acid (PDCA), pyrrole-2,3,4-tricarboxylic acid (iso-PTCA), and pyrrole-2,3,4,5-tetracarboxylic acid (PTeCA) (17,20,21,24). These products are common only to eumelanin and have never been produced by the alkaline hydrogen peroxide oxidation of any other biological material (17,21).…”

Section: Resultsmentioning

confidence: 99%

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Direct chemical evidence for eumelanin pigment from the Jurassic period

Glass

Ito

Wilby

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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169

168

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Melanin is a ubiquitous biological pigment found in bacteria, fungi, plants, and animals. It has a diverse range of ecological and biochemical functions, including display, evasion, photoprotection, detoxification, and metal scavenging. To date, evidence of melanin in fossil organisms has relied entirely on indirect morphological and chemical analyses. Here, we apply direct chemical techniques to categorically demonstrate the preservation of eumelanin in two >160 Ma Jurassic cephalopod ink sacs and to confirm its chemical similarity to the ink of the modern cephalopod, Sepia officinalis. Identification and characterization of degradation-resistant melanin may provide insights into its diverse roles in ancient organisms.

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Section: Resultsmentioning

confidence: 99%

“…Standard of PTeCA was prepared as described in Ward et al (24). Standard of isoPTCA was prepared by a chemically straightforward method by the small molecules facility at Duke University.…”

Section: Methodsmentioning

confidence: 99%

Direct chemical evidence for eumelanin pigment from the Jurassic period

Glass

Ito

Wilby

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

169

168

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“…It is therefore generally believed that the dihydroxyindole moiety is degraded to the pyrrole moiety in the polymeric structure of eumelanins (Pezzella et al., 1997). In fact, free PTCA, in addition to other pyrrole carboxylic acids, can be isolated from eumelanosomes obtained from Sepia, human black hair, and bovine eyes (Ward et al., 2008). The yields of free pyrrole carboxylic acids are surprisingly high, as much as 20% of those after hydrogen peroxide oxidation.…”

Section: Insights From the Comparison Of Synthetic And Natural Melaninsmentioning

confidence: 99%

Current challenges in understanding melanogenesis: bridging chemistry, biological control, morphology, and function

Simon

Peles

Wakamatsu

et al. 2009

Pigment Cell Melanoma Res

337

305

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Melanin is a natural pigment produced within organelles, melanosomes, located in melanocytes. Biological functions of melanosomes are often attributed to the unique chemical properties of the melanins they contain; however, the molecular structure of melanins, the mechanism by which the pigment is produced, and how the pigment is organized within the melanosome remains to be fully understood. In this review, we examine the current understanding of the initial chemical steps in the melanogenesis. Most natural melanins are mixtures of eumelanin and pheomelanin, and so after presenting the current understanding of the individual pigments, we focus on the mixed melanin systems, with a critical eye towards understanding how studies on individual melanin do and do not provide insight in the molecular aspects of their structures. We conclude the review with a discussion of important issues that must be addressed in future research efforts to more fully understand the relationship between molecular and functional properties of this important class of natural pigments.

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“…Ward et al (2008) showed that various melanosomes from Sepia, human black hair, and bovine choroid and iris contain watersoluble PTCA (Free PTCA) at levels one-tenth those of Total PTCA. Free PTCA may be produced by oxidative degradation of DHICA-derived eumelanin in melanosomes in situ (Figure 1).…”

Section: Uva-induced Degradation Of Eumelaninmentioning

confidence: 99%

UVA‐induced oxidative degradation of melanins: fission of indole moiety in eumelanin and conversion to benzothiazole moiety in pheomelanin

Wakamatsu

Nakanishi

Miyazaki

et al. 2012

Pigment Cell Melanoma Res

115

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Subscribe to PCMR and stay up-to-date with the only journal committed to publishing basic research in melanoma and pigment cell biology As a member of the IFPCS or the SMR you automatically get online access to PCMR. Sign up as a member today at www.ifpcs.org or at www.societymelanomaresarch.org SummaryEumelanin is photoprotective while pheomelanin is phototoxic to pigmented tissues. Ultraviolet A (UVA)-induced tanning seems to result from the photooxidation of pre-existing melanin and contributes no photoprotection. However, data available for melanin biodegradation remain limited. In this study, we first examined photodegradation of eumelanin and pheomelanin in human black hairs and found that the ratio of Free (formed by peroxidation in situ) to Total (after hydrogen peroxide oxidation) pyrrole-2,3,5-tricarboxylic acid (PTCA) increases with hair aging, indicating fission of the dihydroxyindole moiety. In red hair, the ratio of thiazole-2,4,5-tricarboxylic acid (TTCA) to 4-amino-3-hydroxyphenylalanine (4-AHP) increases with aging, indicating the conversion from benzothiazine to benzothiazole moiety. These photodegradation of melanins were confirmed by UVA (not UVB) irradiation of melanins from mice and human hairs and synthetic eumelanin and pheomelanin. These results show that both eumelanin and pheomelanin degrade by UVA and that Free ⁄ Total PTCA and TTCA ⁄ 4-AHP ratios serve as sensitive indicators of photodegradation.

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Quantification of Naturally Occurring Pyrrole Acids in Melanosomes^†

Cited by 15 publications

References 22 publications

Direct chemical evidence for eumelanin pigment from the Jurassic period

Direct chemical evidence for eumelanin pigment from the Jurassic period

Current challenges in understanding melanogenesis: bridging chemistry, biological control, morphology, and function

UVA‐induced oxidative degradation of melanins: fission of indole moiety in eumelanin and conversion to benzothiazole moiety in pheomelanin

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Quantification of Naturally Occurring Pyrrole Acids in Melanosomes†

Cited by 15 publications

References 22 publications

Direct chemical evidence for eumelanin pigment from the Jurassic period

Direct chemical evidence for eumelanin pigment from the Jurassic period

Current challenges in understanding melanogenesis: bridging chemistry, biological control, morphology, and function

UVA‐induced oxidative degradation of melanins: fission of indole moiety in eumelanin and conversion to benzothiazole moiety in pheomelanin

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Quantification of Naturally Occurring Pyrrole Acids in Melanosomes^†