Secretory form of Alzheimer amyloid precursor protein 695 in human brain lacks beta/A4 amyloid immunoreactivity.
It is not clear how Alzheimer amyloid precursor proteins (APP) are metabolized in the brain itself. Secretory forms of APP in a phosphate buffer-soluble fraction were purified from post-mortem human brain by heparin-affinity and ion-exchange chromatography and analyzed by N-terminal amino acid sequencing and SDS polyacrylamide gel electrophoresis/immunoblotting. We found apparently similar multi-isoforms of secretory APP (at 93-97, 105-112 and 123 KDa) to those that we have described recently in cerebrospinal fluid. Antisera to the initial part of the beta/A4 sequence labelled only those bands that were found to react with antiserum to the Kunitz-type inhibitor insert of APP, suggesting that beta/A4 amyloid may be generated specifically from APP-695.
Kametani
F
F
Department of Molecular Biology, Tokyo Institute of Psychiatry, Japan.
Tanaka
K
K
Ishii
T
T
Ikeda
S
S
Kennedy
H E
HE
Allsop
D
D
D000328:Adult; D000368:Aged; D000544:Alzheimer Disease / Q000378:metabolism; D000595:Amino Acid Sequence; D000682:Amyloid / Q000378:metabolism*; D016564:Amyloid beta-Protein Precursor / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D001921:Brain / Q000378:metabolism*; D004314:Down Syndrome / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data
D000682:Amyloid; D016564:Amyloid beta-Protein Precursor