FIG. 2.

Biochemical properties of Lyr. (A) Effect of pH on the racemization activity of Lyr toward l-lysine. The buffers used were 50 mM citric acid-Na₂HPO₄, pH 3.5 to 6.5 (•); 50 mM Tris-HCl, pH 6.5 to 8.5 (○); 50 mM K₂HPO₄-KH₂PO₄, pH 6.0 to 8.0 (▴); and 50 mM glycine-NaOH, pH 8.5 to 10.5 (▵). (B) Effect of temperature on racemization activity. (C) Thermostability of purified Lyr. Enzyme activities were assayed after the enzyme was incubated at 50°C. (D) Conversion of l-lysine to d-lysine by recombinant Lyr. Symbols: •, l-lysine; ○, d-lysine.