Substrate specificity of serine racemase. Racemase activity was assayed
at 37°C in media containing 50 mM Tris⋅HCl (pH 8.2), 5 mM
l-serine, 10 μg/ml purified enzyme, 15 μM PLP,
and 10 mM of test compounds. After 1 h, the reaction was
terminated by the addition of 5% trichloroacetic acid (TCA), and the
d-serine produced was monitored by HPLC. The values are
mean ± SEM of three different experiments with three enzyme
preparations. *, Different from control at P
< 0.01. O-P-L-ser,
O-phospho-l-serine; L-homo,
l-homoserine; L-ser O-sulf,
l-serine O-sulfate.