Detection of D-aspartate in tau proteins associated with Alzheimer paired helical filaments.
Paired helical filaments (PHF) characteristic of Alzheimer neurofibrillary lesions are known to contain a modified form of microtubule associated protein tau. These proteins, PHF-tau, differ from normal tau in the extent and the site of phosphorylation. To determine whether PHF-tau, tau proteins from normal adult brains (N-tau), tau proteins from Alzheimer brains not associated with PHF (A-tau), and tau proteins from fetal brains (F-tau) differ in racemization, these proteins were compared for their D-aspartate content. The results demonstrated that PHF-tau contain more D-aspartate than N-tau, A-tau and F-tau. The average percentage D-aspartate for these proteins, after a correction for background, are 4.9%, 2.8%, 1.6%, and 1% for PHF-tau, N-tau, A-tau and F-tau, respectively. It remains to be determined if the increase in D-aspartate is a consequence of PHF formation. It is also unknown if the change in D-aspartate content in PHF-tau is associated with phosphorylation, which alters the susceptibility of tau to proteolysis.
Kenessey
A
A
Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
Yen
S H
SH
Liu
W K
WK
Yang
X R
XR
Dunlop
D S
DS
D000544:Alzheimer Disease / Q000378:metabolism* / Q000473:pathology; D000596:Amino Acids / Q000032:analysis / Q000378:metabolism; D001224:Aspartic Acid / Q000032:analysis / Q000378:metabolism*; D001923:Brain Chemistry / Q000502:physiology; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D006868:Hydrolysis; D015151:Immunoblotting; D016874:Neurofibrillary Tangles / Q000378:metabolism* / Q000473:pathology; D011247:Pregnancy; D016875:tau Proteins / Q000032:analysis / Q000378:metabolism*
D000596:Amino Acids; D016875:tau Proteins; D001224:Aspartic Acid