Control of the Hyaluronidase Activity Towards Hyaluronan by Formation of Electrostatic Complexes: Fundamental and Application Relevance - Natural Polymers, Biopolymers, Biomaterials, and Their Composites, Blends, and IPNs - page 129

Figure 3. Substrate-dependence of the HA hydrolysis catalyzed by BT-HAase in 5 mmol l -1 ammonium
acetate, at pH 5 and at 37°C, for different BT-HAase concentrations ranging from 0.5 to 4 g l -1 . The
number average molar mass of HA was 1.45 × 10 6 g mol -1 . Data from Asteriou et al. (2006).
However, for any HA concentration, the initial hydrolysis rate increased when the
BT-HAase concentration was increased. In fact, analysis of the substrate-dependence
curves obtained for various BT-HAase concentrations indicated that the atypical be-
havior depended on the ratio of the BT-HAase concentration over the HA concentra-
tion since there was a roughly constant ratio between (i) the HA concentration for
which the initial hydrolysis rate was maximum and the BT-HAase concentration and,
(ii) the HA concentration above which the initial rate became close to zero and the
BT-HAase concentration (Asteriou et al., 2006). The substrate-dependence curves
obtained under various ionic strength conditions showed that the existence and the
extent of the atypical behavior of the HA/BT-HAase system strongly depended also
on the ionic strength level (Figure 4). The higher the ionic strength level, the higher
the HA concentration above which the initial hydrolysis rate decreased and, for the
highest ionic strength, no decrease in the initial rate was observed. Moreover, for any