TABLE 1.
Kinetic constants for formyltransferase activities measured in the forward direction
Data are means of triplicate determinations ± S.E.
| Enzyme | Km (5-CHO-THF)a | Km (5-CHO-THF-Glu3)a | Km (l-glutamate) | kcatb |
|---|---|---|---|---|
| μm | μm | μm | min−1 | |
| S. pyogenes FT | 5.4 ± 0.7 | 4.8 ± 1.3 | 1030 ± 30 | 0.13 ± 0.01 |
| P. torridus FT | 0.40 ± 0.04 | 0.70 ± 0.2 | 34 ± 6 | 1.16 ± 0.05 |
| T. acidophilum FT | 3.7 ± 0.5 | 3.8 ± 0.5 | 113 ± 30 | 0.27 ± 0.03 |
| Acidobacteria bacterium FT-CD | 1.8 ± 0.1 | 0.5 ± 0.1 | 276 ± 45 | 0.55 ± 0.03 |
| Porcine FT-CD | 7.2 ± 0.3 | 5.8 ± 0.4 | 206 ± 7 | 0.11 ± 0.01 |
a The cofactors used were the natural (S) form of 5-CHO-THF versus mixed natural and unnatural forms (R,S) of 5-CHO-THF-Glu3, so that Km values for 5-CHO-THF-Glu3 should be halved for comparison with those for 5-CHO-THF.
b Values for kcat were determined with 5-CHO-THF as cofactor; those determined with 5-CHO-THF-Glu3 were similar.