Figure 4

Optimal temperature for activity versus eletrophoretic migration pattern of LAPTc. (A), both native (solid squares) and recombinant (open circles) purified enzymes were incubated with Leu-AMC in reaction buffer at different temperatures for 15 min and the AMC released was measured as described in Experimental Procedures. Standard deviations were less than 10%. LAPTc (B) or rLAPTc (C) was incubated at 20 (lanes 1), 37 (lanes 2), 50 (lanes 3), 60 (lanes 4), 70 (lanes 5) 80 (lanes 6) or 100°C (lanes 7) for 10 min in reaction buffer, followed by 8% SDS-PAGE analysis. Oligomeric (arrow) and monomeric (arrowhead) forms of the enzymes are indicated. Gels were Coomassie-stained.