Protein Modification During Aging of Organism
aDepartment of Biochemistry and Microbiology, Institute of Chemical Technology, Prague , bDepartment of Forensic Medicine, University Hospital, Prague
In the course of aging of organisms, various modifications of side chains of amino acid residues in proteins affect their biological stability and turnover. The main alterations in protein structure are: changes in conformation of proteins, oxidation of amino acid residues (mixed-function oxidation) and racemization of L-amino acids (glutamic and aspartic acids and serine) to corresponding D-forms. D-amino acids were found in bones, teeth, brain and eye lenses. It is generally accepted that the content of D-amino acids slowly increases with age due to a lower metabolic turnover. The discovery of specific D-serine racemase brings a new view of this topic.
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