Adsorption of wild-type and double-mutant cathepsin G to aprotinin-agarose. (A) RBL/CatG and (B) RBL/CatG/Gly₂₀₁/▵Gly₁₉Glu₂₀ cells were labeled with ³⁵S-methionine/³⁵S-cysteine for 40 minutes and chased for 1 and 3 hours. At timed intervals, aliquots of labeled cells (20 × 10⁶) were withdrawn for analyses. Cell lysis and adsorption to aprotinin-agarose were performed as described in the Materials and Methods. No affinity to aprotinin represents labeled protein that did not bind to aprotinin (non-active conformation), whereas material with affinity to aprotinin was eluted after binding (active conformation). After immunoprecipitation and SDS-PAGE, fluorography was performed. The fluorograms were exposed for 7 days.