Summary of 3-OST-3 mutations made corresponding residues in 3-OST-1 and measured enzymatic activity towards 8-mer 1 and 8-mer 3 substrates.
| 3-OST-3 Mutation | Equivalent residues in 3-OST-1 | 8-mer 1 | 8-mer 3 |
|---|---|---|---|
| Wild type | 100%a | 100%b | |
| R173A | S | 45.7% | 17.2% |
| R173S | S | 34.1% | 16.3% |
| R179A | A | 69% | 51.8% |
| R179E | A | 98% | 86.7% |
| R190E | W | 46.8% | 10% |
| R190A | W | 64.2% | 1.9% |
| R190K | W | 94.5% | 85.9% |
| R260E | H | 104.6% | 34.6% |
| R260A | H | 148.2% | 56.4% |
| K259A | N | 29.9% | 3.6% |
| R190E/R260E | W/H | 6.2% | 4.7% |
| S284D | K | 65.6% | 19.1% |
| S284E | K | 61.8% | 22.6% |
a
The 100% activity of 3-OST-3 towards 8-mer 1 was determined to be the transfer of 50 pmoles of sulfo groups per μg of protein in 1 hour.
b
The 100% activity of 3-OST-3 towards 8-mer 3 was determined to be the transfer of 8 pmoles of sulfo groups per μg of protein in 1 hour.