Table 3.

Substrate specificity of serine racemase

Amino acid	Specific activity, μmol/mg per h	% control
l-Serine	4.8	100
l-Alanine	0.012	1.5
l-Threonine	0	0
l-Aspartate	0	0

Racemase activity was assayed at 37°C in a medium containing 50 mM Tris⋅HCl, pH 8.0, 20 mM l-amino acids, 100 μg/ml purified enzyme, 1 mM EDTA, 2 mM DTT, and 15 μM PLP. After 8 h, the reaction was terminated by the addition of 5% TCA, and samples were analyzed by HPLC as described. The data represent a typical experiment that was replicated three times by using different preparations with similar results.