As an 'non-cleavable' control, FabHER-PEG12-biotin (1) was similarly studied in cleavage experiments to ensure that the basis of signal loss was as a result of linker cleavage and not by the interference of the complexes themselves. Signal loss was observed when employing DTT concentrations above 20 mM, despite complexes being captured via a non-cleavable linker (Figure ). At these concentration regimes, a modest mean average signal loss of just 5.6% (± 2.5%) was observed, indicating that -for the example of FabHER-PD-PEG3-SS-PEG4-biotin -complex release is predominantly the result of linker cleavage and triggered by specific conditions.