Altered aspartate in Alzheimer neurofibrillary tangles

Normal protein-boundl-aspartyl/l-asparaginyl residues may undergo post-translational modification by racemization tod-aspartate, or by isomerization to thel-isoaspartyl form in which the peptide chain links through the beta carboxyl group of the residue. Based on preliminary results reported here, proteins associated with Alzheimer neurofibrillary tangle preparations contain a significantly greater number of these modified aspartyl residues than the unaffected proteins from the surrounding gray matter or in comparable preparations from normal brains.