Fig. 4

Extracellular carboxypeptidase Y and overall proteolytic activity present in the supernatant of HOPS and CORVET mutants. CPY in the supernatant was detected by Western blot (a) and the proteolytic activity was measured by a protease activity assay (b). Proteolytic activity is given as µg/mL tryptic equivalents. The technical variance of the method was approximately 10%. The results of one representative measurement are shown. nd: not detectable