TABLE 3.

Hydrolysis of different amides by enantioselective amidases from R. erythropolis MP50 and A. tumefaciens d3^a

Substrate	Structure	Relative activity (%)		Enantiomeric ratio
		MP50	d3b	MP50	d3b
2-Phenylpropionamide		100	100	>100	>100
2-Methyl-3-phenylpropionamide		104 ± 21	37	15	>100
2-Methoxyphenylacetamide		20 ± 1	3	>100	36
2-Chlorophenylacetamide		112 ± 6	56	>100	>100
Mandeloamide		25 ± 6	15	8	6

^aThe reaction mixtures were 0.5 ml and contained 15 μmol of Tris-HCl (pH 7.5), 0.25 μmol of the respective amide, and purified amidase (1.4 to 3.2 mg) from R. erythropolis MP50. The reference data for the amidase from A. tumefaciens d3 were determined in 25 μM Na phosphate or K phosphate buffer (pH 7.4) with cell extracts (0.01 to 0.6 mg) from E. coli JM109 (pST2WT) (60). The specific activities of the purified amidase from strain MP50 and the cell extract from E. coli JM109 pST2WT with 2-phenylpropionamide as substrate were 3.4 ± 0.7 and 0.39 U/mg of protein, respectively. The tests were performed in duplicate, and the standard deviations are given.

^bData were taken from a previous report (60), with permission.