The affinity of melanin for inorganic ions

Potts, Albert M.; Au, Pin Chit

doi:10.1016/0014-4835(76)90186-x

Cited by 114 publications

(65 citation statements)

References 14 publications

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“…As there appears to be no marked affinity of sodium ions for melanin [32][33][34], we focused our theoretical investigations on the effect of electrolyte concentration on the diffusive behavior of the mobile ions. In fact, our model, which does not account for adsorption effects, is also able to provide an explanation for the dependence of the zeta potential on the NaCl concentration.…”

Section: Discussionmentioning

confidence: 99%

Linking aggregation of Aspergillus niger spores to surface electrostatics: a theoretical approach

Wargenau¹,

Kampen²,

Kwade³

2013

Biointerphases

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The effect of medium pH on conidial aggregation during submerged cultivation of Aspergillus niger is considered to originate from the electrostatic surface properties of the spores. As previously shown, these properties are greatly influenced by the presence of a melanin-containing surface coating covering the outer spore wall layer. The present study was designed to elucidate the impact of such a coating on the spores' surface potential and their electrostatic repulsion under acidic conditions. A Poisson-Boltzmann model was proposed and potential profiles across the surface coating of noninteracting and interacting spores were calculated. The surface potentials thus obtained were in line with the observed pH dependence of the zeta potential. This dependence was consistent with the outcome of aggregation experiments. Apparently contradictory results regarding the zeta potential and the aggregation behavior of the spores were obtained when the ionic strength was varied. However, both of these observations could be explained by the model.

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Section: Discussionmentioning

confidence: 99%

Linking aggregation of Aspergillus niger spores to surface electrostatics: a theoretical approach

Wargenau¹,

Kampen²,

Kwade³

2013

Biointerphases

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“…18 The percentage of metal cations remaining in solution was used to estimate the metal binding affinity. Implicit in this analysis are two assumptions, the validity of which is not clear.…”

Section: Binding Sitesmentioning

confidence: 99%

“…16,17 The functional groups associated with these molecular building blocks are central to the metal coordinating abilities exhibited by melanins. 4,7,[18][19][20] In situ, with the exception of NM, melanin is generally deposited in melanosomes, specialized organelles in pigment generating cells. Similar to most cellular organelles, melanosomes are membrane-bound structures containing a variety of molecular species, including lipids, proteins, and melanin.…”

Section: Introductionmentioning

confidence: 99%

Current Understanding of the Binding Sites, Capacity, Affinity, and Biological Significance of Metals in Melanin

2007

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Metal chelation is often invoked as one of the main biological functions of melanin. In order to understand the interaction between metals and melanin, extensive studies have been carried out to determine the nature of the metal binding sites, binding capacity and affinity. These data are central to efforts aimed at elucidating the role metal binding plays in determining the physical, structural, biological, and photochemical properties of melanin. This article examines the current state of understanding of this field.

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“…Drugs like chlorpromazine (Basu et al 1989;Robins, 19911, chloroquine (Lindquist, 19731, and atropine (Emiru, 1971) bind strongly to melanin. The binding of several metals, i.e., zinc, copper, nickel, and cobalt, has been investigated, but mostly in their roles in melanin synthesis (Pfeiffer and Mailloux, 1989;Potts, 1976). These valid experiments do not justify claims that "melanin can bind and release most elements known on earth" (Barnes, 1988:37).…”

Section: Physical and Chemical Propertiesmentioning

confidence: 99%

Melanin, afrocentricity, and pseudoscience

Montellano

1993

Am. J. Phys. Anthropol.

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A component of the Afrocentric movement has incorporated a theory that black people, including ancient Egyptians, have superior mental, physical, and paranormal powers because they have more melanin both in their skin and in their brains. By extension it is also claimed that black people have more melatonin and P-MSH in their systems and that these compounds also contribute to the superiority of people of color over whites. In this paper, these claims are detailed and refuted. A review of the genetics and biochemistry of human pigmentation shows that all humans have similar amounts of neuromelanin (brain melanin), and that its concentration is absolutely independent of skin color; that adult humans do not synthesize P-MSH; and that human melatonin has no clearly demonstrable physiological function and no relationship to skin color. "Melanists" also distort human evolution by claiming that European whites are descendants of negroid albinos. The main problems posed by this ideological movement are that it will increase the already rampant scientific illiteracy in this country, it will contribute to further widening the gap between the races, and, most importantly, it is being introduced into the public school curriculum under the guise of multicultural education.

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The affinity of melanin for inorganic ions

Cited by 114 publications

References 14 publications

Linking aggregation of Aspergillus niger spores to surface electrostatics: a theoretical approach

Linking aggregation of Aspergillus niger spores to surface electrostatics: a theoretical approach

Current Understanding of the Binding Sites, Capacity, Affinity, and Biological Significance of Metals in Melanin

Melanin, afrocentricity, and pseudoscience

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