Optimized Purification of Human Amyloid‐beta (Aβ) 40 and Aβ42 Using an <i>E. coli</i> Expression System

Amyloid-beta (Aβ) peptides, primarily Aβ40 and Aβ42, are central to the formation of amyloid plaques, a pathological hallmark of Alzheimer's disease (AD). These peptides, derived from the amyloid precursor protein (APP), are aggregation prone and neurotoxic. Experimental studies aimed at understanding Aβ aggregation and interaction require pure, monomeric peptides with the native sequences, including the absence of an N-terminal methionine. We present an optimized protocol for producing recombinant human Aβ40 and Aβ42 using a SUMO fusion system in Escherichia coli. Cleavage of the SUMO tag enables recovery of native-sequence peptides, producing physiologically relevant monomers with high yield and purity. This method eliminates the need for chemical synthesis and offers a reliable and cost-effective approach to producing recombinant Aβ suitable for aggregation studies, structural analyses, and interaction assays. The resulting peptides closely mimic endogenous Aβ, facilitating accurate models of Alzheimer's disease pathogenesis and supporting future therapeutics development. © 2025 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol: Expression and purification of Aβ40 and Aβ42 from Escherichia coli.