Figure 6.

ATPase stimulation and peptide transport by sterically restricted peptides. To correlate vanadate-sensitive ATPase activity and peptide transport, the release of inorganic γ-³²P_i after 4 min at 32°C and the peptide transport were analyzed in presence of 2.5 μM ARDNATK(-ɛK_n)DY carrying different polylysine extensions (n). IC₅₀ were taken from (12) (a) or determined by peptide competition assays as described (11) (b). Details of the ATPase, peptide-binding, and transport assay are described in Materials and Methods. Data are background-subtracted and obtained from duplicate measurements.