Alzheimer's disease: distribution of protein on sucrose density gradient centrifugation

Material has been examined from eighteen brains, postmortem and from 3 cortical biopsies. The case were classified on clinical and morphological criteria and include cases of dementia and of nonneurological disease. Fractions were isolated from homogenates of neocortex and caudate nucleus by means of discontinuous sucorse density gradient centrifugation. The fractions were analysed for protein content. The mean protein content of fraction 1, at the interphase between 0.32 M and 0.8 M sucrose, from the cortex of the 6 Alzheimer cases was reduced. (P less than 0.005) by 25%. This deficit in protein content represents less than 5% of the total tissue protein. There were no significant differences in the protein content between other fractions from the control and Alzheimer cases.