Figure 4.

Destruction of l-serine O-sulfate by serine racemase. (A) Serine racemase (10 μg/ml) was incubated for 2 h with 10 mM l-serine O-sulfate in media containing 50 mM Tris⋅HCl (pH 8.2) and 15 μM PLP. The HPLC traces show the content of l-serine O-sulfate before and after incubation with the enzyme. l-homocysteic acid (2.5 nmol) was used as an internal standard. (B) Time course of l-serine O-sulfate consumption. Conditions were the same as in A. The values are representative of three different experiments with different enzyme preparations.