Identification of Proteins Modified by Protein (D-Aspartyl/L-Isoaspartyl) Carboxyl Methyltransferase

  • Darin J. Weber
  • Philip N. McFadden
Part of the Springer Protocols Handbooks book series (SPH)


The several classes of S-adenosylmethionine-dependent protein methyltransferases are distinguishable by the type of amino acid they modify in a substrate protein. The protein carboxyl methyltransferases constitute the subclass of enzymes that incorporate a methyl group into a methyl ester linkage with the carboxyl groups of proteins. Of these, protein (D-aspartyl/L-isoaspartyl) carboxyl methyltransferase, EC (PCM) specifically methyl esterifies aspartyl residues that through age-dependent alterations are in either the D-aspartyl or the L-isoaspartyl configuration (1,2). There are two major reasons for wishing to know the identity of protein substrates for PCM. First, the proteins that are methylated by PCM in the living cell, most of which have not yet been identified, are facets in the age-dependent metabolism of cells. Second, the fact that PCM can methylate many proteins in vitro, including products of overexpression systems, can be taken as evidence of spontaneous damage that has occurred in these proteins since the time of their translation.


Scintillation Vial Scintillation Fluid Solubilization Buffer Electrode Buffer Cationic Detergent 
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Copyright information

© Humana Press Inc., Totowa, NJ 2002

Authors and Affiliations

  • Darin J. Weber
    • 1
  • Philip N. McFadden
    • 1
  1. 1.Department of Biochemistry and BiophysicsOregon State UniversityCorvallis

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