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 143

Figure 13. Substrate-dependence of the HA hydrolysis catalyzed by H460M-HAase in 0.15 mol
l -1 ammonium nitrate, at pH 3.5 and at 37°C, for a H460M-HAase concentration of 51 U l -1 . The
H460M-HAase concentration was determined according to the procedure described in Delpech
et al. (1995). The number average molar mass of HA was 1.45 × 10 6 g mol -1 . (unpublished personal
data).
Moreover, Delpech and his collaborators showed that the H460M-HAase activ-
ity, in the presence of a 0.2 mol l -1 ionic strength and at pH 3.8, was dependent on
the BSA concentration in the reaction medium: when the BSA concentration was in-
creased, H460M-HAase activity increased reached a maximum and then decreased
(Maingonnat et al., 1999). In good agreement with the results we obtained with LYS
and poly-L-lysine, they found that foetal calf serum immunoglobulins, human serum
albumin, hemoglobin and transferrin were also able to increase the H460M-HAase
activity (Maingonnat et al., 1999). All these results clearly indicate that, in the same
way as for BT-HAase, the enzymatic activity of the human tumoral HAase (H460M-
HAase) can be either enhanced or suppressed by non-catalytic proteins according to
their concentration.
The group of Delpech extensively studied hyaluronectin (HN), a hayladherin
which is the HA binding moiety of the proteoglycan versican. They showed that HN
has a great and specific affinity for HA (Delpech et al., 1995). Like for many other
hyaladherins, electrostatic interactions play an important role in the HN binding to HA
(Day, 2001). Very interestingly, Delpech and his collaborators showed that, according