. Author manuscript; available in PMC: 2011 Apr 1.

Published in final edited form as: J Mol Biol. 2010 Jul 23;402(2):399–411. doi: 10.1016/j.jmb.2010.07.036

Table 3.

Kinetic constants for wild-type and mutant – 15/GTB UDP-Gal and UDP-GalNAc glycosyltransfer and UDP-Gal hydrolysis

Substrate	UDP-Gal			UDP-Gal hydrolysis		UDP-GalNAc
Substrate	K_A^a (μM)	K_B^b (μM)	k_cat(s⁻¹)	K_m (μM)	k_cat (s⁻¹)	K_A^a (μM)	K_B^b (μM)	k_cat (s⁻¹)
– 15 GTB (amino acids 68–354)	55±13	45±6	7.3±0.7	47±20	0.0022±0.0002	300±55	145±20	0.41±0.04
GTB/C80S/C196S	32±6	23±6	5.6±0.4	22±9	0.0027±0.0003	300±70	210±40	0.70±0.02
GTB/C89S/C196S/C209S	350±80	78±13	8±1.0	120±40	0.0012±0.0001	200±40	320±70	0.15±0.03

K_A is the Michaelis-Menten constant K_m for the acceptor [Fucα1–2Galβ-O-(CH₂)₇CH₃].

K_B is the Michaelis-Menten constant K_m for the donor (UDP-Gal or UDP-GalNAc).