Table 3.
Effects of metal ions, EDTA and DTT on the α2,6-sialyltransferase activity of Δ15Pd2,6ST(N) and Δ112Pd2,6ST(N)a
| Reactions | Δ15Pd2,6ST(N) | Δ112Pd2,6ST(N) |
|---|---|---|
| Control | 50% | 43% |
| MgCl2 | 48% | 43–44% |
| 5 mM MnCl2 | 44% | 39% |
| 10 mM MnCl2 | 28% | 38% |
| 20 mM MnCl2 | 15% | 21% |
| DTT | 51–52% | 45–46% |
| 5 mM EDTA | 43% | 35% |
a
The numbers in the table represent the percentage conversions (Standard Deviation ≤ 1.4%). The activity was determined in duplicate at 37 °C for 30 min (100% conversion was defined as the formation of 1 mM Neu5Acα2,6LacMU). Different concentrations (5 mM, 10 mM, and 20 mM) of MgCl2 or MnCl2, 5 mM EDTA, and various concentrations (0.2 mM, 1 mM, and 5 mM) of DTT were used in a reaction mixture of 20μl containing Tris-HCl buffer (pH 8.5, 100 mM), CMP-Neu5Ac (1 mM), LacMU (1 mM), and Δ15Pd2,6ST(N) (190 ng) or Δ112Pd2,6ST(N) (285ng). Reaction in the absence of DTT, EDTA, or metal ion was used as a control.