Figure 3.

β-Lactamase activity of the gradient fractions. Strain H393 (sec18) was incubated at 37°C (A), then at 50°C (B), and thereafter for 6 h at 24°C with CHX (C). The cells were lysed and subjected to sucrose gradient centrifugation as described in Fig. 2, A–C. The fractions were assayed for β-lactamase activity.