TABLE 2.
Enzymatic activity of hHYAL4/mHyal4 mutants
Nonlabeled CS-A was incubated individually with the purified protein (125 ng each) at 37 °C in 50 mm acetate buffer, pH 4.5, for 30 min. Enzymatic activities of hHYAL4/mHyal4 mutants toward CS-A are expressed as a percentage of that of hHYAL4.
| Constructs | Relative activity | Proportion of A unita | Substrate preference |
|---|---|---|---|
| % | |||
| hHYAL4 (hhhh) | 100 | 22 | Human type |
| mHyal4 (mmmm) | 450 | 95 | Mouse type |
| h(I) | 310 | 35 | Human type |
| h(II) | 140 | 20 | Human type |
| h(III) | NDb | ND | No activity |
| h(I)(II) | 420 | 36 | Human type |
| h(I)(III) | 60 | 94 | Mouse type |
| h(II)(III) | ND | ND | No activity |
| h(I)(II)(III) | 90 | 93 | Mouse type |
| h(I)(III/Q305R) | 460 | 30 | Human type |
| h(I)(III/K309R,E310D) | 150 | 96 | Mouse type |
| h(I)(III/L314F) | 70 | 95 | Mouse type |
| h(I)(R305Q) | 300 | 97 | Mouse type |
| m(A261S,V262I,S263G,I264V,R265W)(Q305R) | 63 | 47 | Human type |
a The proportion of the reducing terminal disaccharide of oligosaccharides generated by the digestion of CS-A.
b ND, not detected.