Abstract
The age-related accumulation of abnormal forms of enzymes is attributable to posttranslational modification of protein structure and to a progressive loss with age of proteases that preferentially degrade the modified forms. The protein modifications include, but are not limited to: the oxidation of amino acid side chains (especially, side chains of prolyl, arginyl, lysyl and histidinyl residues) by mixed-function oxidation systems; the deamidation of asparaginyl and glutaminyl residues; the racemization and isomerization of aspartyl and asparaginyl residues; the isomerization of prolyl residues; the oxidation of cysteine sulfhydryl groups; and spontaneous changes in protein conformation that are apparently unlinked to changes in amino acid composition. Evidence supporting the roles of these protein modifications and of the proteases that degrade abnormal enzymes during aging is discussed, as well as a consideration of some technical limitations of the methods used in their study.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
