Fig. 4.

Influence of the substrate concentration on PmHS2 activity during 180 to 360 min of incubation. Purified PmHS2 (55–60 μg/ml) was assayed in the standard polymerization buffer described in the Materials and methods section with increasing substrate concentration ranging from 1 up to 20 mM of both nucleotide sugars. The specific activity observed during 180 to 360 min of incubation for the following substrate concentrations 1 (Δ), 5 (○), and 20 mM (•) of both UDP-GlcUA and UDP-GlcNAc was, respectively, about 0.080, 0.145, and 0.128 nmol/µg/min