Combined use of micro-preparative gel electrophoresis and reversed-phase high-performance liquid chromatography for purification of amyloid beta peptides deposited in brains of Alzheimer's disease patients

A new micro-technique is developed for purification of amyloid beta peptides (A beta) extracted from brain tissues of patients with Alzheimer's disease (AD). It includes SDS-polyacrylamide gel electrophoresis of the extracted brain tissue material, electroblotting onto supporting membranes, and reversed-phase HPLC of the proteins eluted from membranes. By this technique, the extracted A beta are first separated electrophoretically from the higher and lower molecular mass tissue components, and then purified by reversed-phase HPLC from the contaminants having similar molecular masses, but different retention times on the column. In contrast to the common large-scale isolation procedures employing density gradient centrifugation, enzymatic digestions and size-exclusion chromatography, the developed micro-technique might be applied for biochemical analysis of A beta contained in small AD brain tissue specimens.