FIGURE 1.

Removal of artificial N-terminal extension releases the proteolytic activity of GS-SplB and l-SplB. A, GS-SplB was incubated with APP, and the proteolytic activity against Ac-WELQ-ACC (specific for SplB) was monitored. The activity is represented as a percentage of the maximum activity observed for the same concentration of SplB protease as the initial concentration of GS-SplB. Bestatin inhibits AAP activity. Samples were collected at indicated time points and subjected to N-terminal Edman degradation sequencing (results shown at the bottom of the panel). Activity of AAP remained unchanged during the experiment as monitored using Leu-pNa (not shown). B, same as in A but for L-SplB.