Figure 2.

A, Effect of culture age and cultivation temperature on pectate lyase activity in the culture medium of P. pastoris. Pectate lyase activity at 25°C (▄ ). Pectate lyase activity at 30°C (▴ ). B, Effect of temperature on pectate lyase activity. Pectate lyase expressed in P. pastoris and E. coli was added to 50 mM Gly–NaOH buffer (pH 9.4) and incubated at different temperatures for 10 min. Maximum activity was set to 100%. A: recombinant PEL168E; and B: PEL168P. C, Effect of pH on pectate lyase activity. PEL168P and PEL168E were respectively incubated for 10 min at 50°C at the indicated pH values in 50 mM different buffer [Na₂HPO₄–citric acid (pH 4.0–6.0), sodium phosphate (pH 6.0–7.5), Tris–HCl (pH 7.5–8.8) and glycine–NaOH (8.8–10.6)]. Maximum activity was set to 100%. A, recombinant PEL168E; and B, PEL168P. D, Temperature stability of the purified pectate lyase. PEL168P and PEL168E were respectively incubated in the absence of substrate for 30 min at 60°C, and residual activity was measured as described in the methods section. The start-time enzyme activity was set to 100%. A: recombinant PEL168P; and B: PEL168E.