Table 2.

Racemization of l-Serine

Time, h	[l-Serine]	[d-Serine]
	mM
0	4.00	0.0007
0.5	3.96	0.042
1	3.93	0.101
4	3.65	0.342

Racemase activity was assayed at 37°C in a medium containing 50 mM Tris⋅HCl, pH 8.0, 4 mM l-serine, 40 μg/ml purified enzyme, 1 mM EDTA, 2 mM DTT, and 15 μM PLP. Samples were analyzed for amino acid emantiomers by HPLC as described.