TABLE 2.

Substrate specificity of ApsC towards (N-acetylated) amino acid-pNA or amino acid-βNA substrates

Substratea	Relative activity (%) (mean ± SD)
F-βNA	100 ± 1.1
Y-βNA	72 ± 2.5
W-βNA	2 ± 0.77
L-βNA	6 ± 0.46
Other amino acid-βNA	<1
F-pNA	100 ± 0.40
L-pNA	6 ± 0.32
M-pNA	6 ± 0.60
NacA-pNA	<1
Other amino acid-pNA	<1

^aOne hundred percent F-pNA activity is 189 U mg⁻¹. NacA, N-acetylalanine, Other pNA substrates tested include A-pNA, K-pNA, R-pNA, G-pNA, I-pNA, V-pNA, and E-pNA; other βNA substrates tested include N-βNA, T-βNA, S-βNA, and H-βNA.