FIG. 4.

Trypsin cleavage of PBP 2a* leading to TP domain isolation. (A) Proteins were separated by SDS–12.5% PAGE and stained with Coomassie blue. The N-terminal sequence of each product is indicated on the right. (B) Fluorogram of a dried gel from SDS–12.5% PAGE of proteins (2 μg) labelled with [³H]benzylpenicillin prior to the migration. Digestions were performed at 37°C for 30 min. Lanes: 1, molecular mass markers; 2, undigested PBP 2a*; 3, trypsin/PBP 2a* ratio of 1:500 (wt/wt); 4, trypsin/PBP 2a* ratio of 1:100 (wt/wt); 5, trypsin/PBP 2a* ratio of 1:50 (wt/wt); 6, trypsin/PBP 2a* ratio of 1:20 (wt/wt).