Complement C1s/C2 FRET Substrate, FAM/QXL520

An internally quenched peptide derived from complement component C2 and designed to measure C1s protease activity. C1s initiates the classical complement cascade by processing C4 and C2. Cleavage separates 5-FAM from QXL520 and produces a green fluorescence signal.

• C1s protease activity assays
• classical complement pathway research
• complement inhibitor screening
• FRET serine-protease assays

This is a peptide model of a C2 cleavage region rather than intact complement C2. Use purified C1s or pathway-specific controls for complex samples.

1. Structural basis for complement activation by C1s