Document Detail


Direct observation of NH2* reactions with oxygen, amino acids, and melanins.
MedLine Citation:
PMID:  18215026     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We report the direct observation of the quenching of the weakly absorbing transient due to the amino radical by oxygen and, hence determine, by a totally direct method, the corresponding rate constant (k = (1.1 +/- 0.1) x 10(9) dm3 mol(-1) s(-1)). We also report the rate constants for the reactions of the amino radical with several amino acids and models of black eumelanin and blond/red phaeomelanin. These reactions lead to a mechanism, based on free radicals, that can explain why ammonia is useful in commercial hair (melanin) bleaching, avoiding excessive amino acid (hair protein) damage.
Authors:
K Clarke; R Edge; V Johnson; E J Land; S Navaratnam; T G Truscott
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-01-24
Journal Detail:
Title:  The journal of physical chemistry. A     Volume:  112     ISSN:  1089-5639     ISO Abbreviation:  J Phys Chem A     Publication Date:  2008 Feb 
Date Detail:
Created Date:  2008-02-07     Completed Date:  2008-04-11     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9890903     Medline TA:  J Phys Chem A     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1234-7     Citation Subset:  IM    
Affiliation:
Chemistry Section, School of Physical and Geographical Sciences, Keele University, Staffs ST5 5BG, UK.
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MeSH Terms
Descriptor/Qualifier:
Amines / chemistry*
Amino Acids / chemistry*
Ammonia / chemistry
Hydrogen Peroxide / chemistry
Hydroxyl Radical / chemistry
Kinetics
Melanins / chemistry*
Oxidation-Reduction
Oxygen / chemistry*
Pulse Radiolysis
Spectrum Analysis
Chemical
Reg. No./Substance:
0/Amines; 0/Amino Acids; 0/Melanins; 12627-61-1/phaeomelanin; 3352-57-6/Hydroxyl Radical; 7664-41-7/Ammonia; 7722-84-1/Hydrogen Peroxide; 7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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