Table 2. In vitro β(1,6)-N-acetylglucosaminyltransferase activity of C2GnT-I and its glycomutants.

Detergent cell extracts were assayed for β(1,6)-N-acetylglucosaminyltransferase activity as described in [30] using the synthetic oligosaccharide Galβ1,3GalNAc-O-p-nitrophenyl as an acceptor. Unless otherwise specified, the activity was determined as nmol of GlcNAc transferred·(nmol of EGFP)⁻¹·h⁻¹ (ϵ=55000 M⁻¹·cm⁻¹).

	Catalytic activity [nmol·(nmol of EGFP)−1·h−1]	Inhibition (%)
Wild-type	1.92±0.20
T60A	1.22±0.15	36.4
T97A	0.45±0.07	76.6
T60A/T97A	0.12±0.02	93.7
Control	116.65*
TM-treated	58.41*	50.1

*The activity was calculated as nmol of GlcNAc transferred·(mg of protein)⁻¹·h⁻¹.