TABLE 4.
Hydrolysis and transfer of donor substrates by wild type K4CP, and the mutant constructs 239ACA241 and 519ASA521
The hydrolysis of Km (μm) of UDP-GalNAc and UDP-GlcA and the transfer activity (pmol/min/μg of protein) of UDP-GalNAc and UDP-GlcNAc by wild type, 239ACA241 and 519ASA521 are shown. ND, no detectable transfer. Assay mixtures containing radioactive plus nonradioactive substrates at final concentrations of 1.6, 3.2, 6.4, 9.6, 16.0, 32.0, 64.0, 96.0, 128.0, and 200.0 μm were incubated with 53 μ g of protein for 1 h at 30 °C.
| Substrate | Wild | 239ACA241 | 519ASA521 | |
|---|---|---|---|---|
| Hydrolysis | UDP-GlcA | ND | ND | ND |
| UDP-GalNAc | 65.09 | 135.31 | 24.27 | |
| Transfer activity | UDP-GalNAc | 5.895 | ND | 5.469 |
| UDP-GlcNAc | 0.394 | ND | 0.534 |