. Author manuscript; available in PMC: 2013 Nov 13.

Published in final edited form as: Biochemistry. 2012 Oct 30;51(45):9245–9255. doi: 10.1021/bi3006829

Table 2.

Steady State Kinetic Parameters for ΨMP Glycosidase and Mutants^a.

Enzyme	k_cat (s^-1)	K_m (μM)	k_cat/ K_m (M^-1 s^-1)
ΨMP glycosidase	3.74 ± 0.14	169.6 ± 21.6	(22 ± 3.6) × 10³
K166A	0.0013 ± 0.00005	162.4 ± 23.5	8 ± 1.5
E31A	0.0005 ± 0.00005	191 ± 39.3	2.6 ± 0.8
K93A	0.22 ± 0.007	300.5 ± 21.8	(0.73 ± 0.076)×10³
N289A	0.23 ± 0.007	214.2 ± 18.7	(1.1 ± 0.13) × 10³
D149A	NA^b	NA	NA

All the kinetic parameters were determined by monitoring the conversion of uracil to ΨMP under a saturating R5P concentration; k_cat and K_m are determined for uracil.

No activity was detected under standard assay conditions.