Document Detail

The effect of neighboring amino acid residues and solution environment on the oxidative stability of tyrosine in small peptides.
MedLine Citation:
PMID:  18181523     Owner:  NLM     Status:  MEDLINE    
The effects of neighboring residues and formulation variables on tyrosine oxidation were investigated in model dipeptides (glysyl tyrosine, N-acetyl tyrosine, glutamyl tyrosine, and tyrosyl arginine) and tripeptide (lysyl tyrosyl lysine). The tyrosyl peptides were oxidized by light under alkaline conditions by a zero-order reaction. The rate of the photoreaction was dependent on tyrosyl pK(a), which was perturbed by the presence of neighboring charged amino acid residues. The strength of light exposure, oxygen headspace, and the presence of cationic surfactant, cetyltrimethylammonia chloride had a significant effect on the kinetics of tyrosyl photo-oxidation. Tyrosine and model tyrosyl peptides were also oxidized by hydrogen peroxide/metal ions at neutral pH. Metal-catalyzed oxidation followed first-order kinetics. Adjacent negatively charged amino acids accelerated tyrosine oxidation owing to affinity of the negative charges to metal-ions, whereas positively charged amino acid residues disfavored the reaction. The oxidation of tyrosine in peptides was greatly affected by the presence of adjacent charged residues, and the extent of the effect depended on the solution environment.
Jian Zhang; Devendra S Kalonia
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2007-12-07
Journal Detail:
Title:  AAPS PharmSciTech     Volume:  8     ISSN:  1530-9932     ISO Abbreviation:  AAPS PharmSciTech     Publication Date:  2007  
Date Detail:
Created Date:  2008-01-09     Completed Date:  2008-01-24     Revised Date:  2010-12-28    
Medline Journal Info:
Nlm Unique ID:  100960111     Medline TA:  AAPS PharmSciTech     Country:  United States    
Other Details:
Languages:  eng     Pagination:  E102     Citation Subset:  IM    
Department of Pharmaceutical Science, School of Pharmacy, University of Connecticut, Storrs, CT 06269, USA.
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MeSH Terms
Amino Acids / chemistry*,  radiation effects
Antioxidants / chemistry
Cetrimonium Compounds / chemistry
Chemistry, Pharmaceutical
Drug Stability
Hydrogen Peroxide / chemistry
Hydrogen-Ion Concentration
Metals / chemistry
Oligopeptides / chemistry*,  radiation effects
Osmolar Concentration
Oxygen / chemistry
Surface-Active Agents / chemistry
Technology, Pharmaceutical / methods
Tyrosine / chemistry*,  radiation effects
Reg. No./Substance:
0/Amino Acids; 0/Antioxidants; 0/Cetrimonium Compounds; 0/Metals; 0/Oligopeptides; 0/Solutions; 0/Surface-Active Agents; 55520-40-6/Tyrosine; 6899-10-1/cetrimonium; 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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