Table 1.

Kinetic constants of recombinant sucrose synthases and cellulose synthase for UDP-glucose and sucrose

Enzyme	Km, mM		Vmax, nmol per min per μg
	UDP-glucose	Sucrose	UDP-glucose	Sucrose
SuSy (wild type)	0.40*	161*	1.67*	0.24*
SuSy (mutant)	0.45*	23*	1.00*	0.11*
Cellulose synthase + SuSy  (mutant)	0.20	ND	0.03	ND
+10 mM UDP	—	0.33	—	0.06
+1 mM UDP	—	0.42	—	0.12
+0.1 mM UDP	—	0.83	—	0.28

SuSy, sucrose synthase. 

^*Conditions were the same as those of the standard assay, except for the concentrations of UDP-glucose or sucrose (8).