Sequencing and Identification of Proteins from Mixtures

This application note presents a technical report on the sequencing and identification of proteins from five-protein mixtures using Quantum-Si’s Platinum® instrument. The document outlines the limitations of traditional protein detection methods that rely on antibodies or targeted reagents, which often struggle to identify proteins with variant peptide sequences. The Platinum® instrument offers a novel approach by directly sequencing proteins, thereby eliminating the need for antibody-based assays. The report details the successful identification of five recombinant proteins within a mixture, demonstrating the feasibility of detecting multiple proteins without the constraints of antibody specificity. The methodology section describes the library preparation workflow, which includes reduction, alkylation, and endopeptidase digestion of intact proteins, followed by sequencing on the Platinum® instrument. Results indicate that the new workflow allows for efficient identification of multiple proteins in a single sequencing run, enhancing throughput and process efficiency. The findings support the applicability of the Quantum-Si Platinum sequencing platform for complex protein sample analysis.