Quantum-Si Incorporated (NASDAQ:QSI) ("Quantum-Si," "QSI" or the "Company"), a proteomics company redefining protein analysis through single-molecule protein sequencing, today announced that it has demonstrated detection of 19 amino acids in its Proteus™ development program and is now working to deploy that capability into a developmental sequencing kit for routine use on integrated Proteus instruments. Building on the interim Proteus results presented at the 2026 World HUPO Congress, this latest milestone reflects continued progress in the Company’s amino acid recognizer program and reinforces its confidence that detection of all 20 amino acids is well within reach by year-end 2026.