Table 2. Substrate specificity of GuUGDs.

Nucleotide-sugar	Relative enzyme activity of isoforms (%)
	GuUGD1	GuUGD2	GuUGD3	GuUGD4	GuUGD5
UDP-glucose	100	100	100	100	n.d.
UDP-galactose	n.d.	n.d.	n.d.	15	n.d.
UDP-N-acetylglucosamine	n.d.	n.d.	n.d.	10	n.d.

We calculated enzyme activity based on initial velocity within 10 min measured by monitoring the conversion of NAD(P)⁺ to NAD(P)H, detected by the absorbance at 340 nm. 100% corresponds to the activity indicated in the standard assay with UDP-glucose as a substrate and NAD⁺ as a cofactor. n.d., not detected.