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How Do Enzymes Wear Out? Effects of Posttranslational Modifications on Structure and Stability of Proteins; The Triosephosphate Isomerase Model

Triosephosphate isomerase (EC 5.3.1.1., TPI) undergoes specific posttranslational modifications (deamidation and oxidation) which are believed to initiate protein turnover by destabilization of the dimer. The crystal structures, amino acid sequences, and aging related changes of TPI from various species have been independently characterized by several laboratories. TPI has thus become the prototype enzyme for examining the initial steps in protein turnover. The binding of substrate enhances the specific deamidation of the mammalian enzyme, and a general mechanism of 'molecular wear and tear' [Gracy, R. W., Yiiksel, K. 0., Chapman, M. L., and Dimitrijevich, S. D. (1990) in Isozymes-Structure, Function and Use in Biology and Medicine (Ogita, Z-I., and Markert, C. L., Eds) pp. 787-817, Wiley-Liss, New York] has been proposed to explain how enzymes may wear out.

Identiferoai:union.ndltd.org:unt.edu/info:ark/67531/metadc798116
Date12 1900
CreatorsSun, An-Qiang
PublisherUniversity of North Texas
Source SetsUniversity of North Texas
LanguageEnglish
Detected LanguageEnglish
TypeThesis or Dissertation
Formatxi, 193 leaves : ill., Text
RightsPublic, Sun, An-Qiang, Copyright, Copyright is held by the author, unless otherwise noted. All rights

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