Table III.
Substrate specificity of β-Ala NMTase expressed in yeast (pYES-NMTase)
Relative activities are shown as percentage of that found with β-Ala. Specific activity with β-Ala (100%) was 105.2 nmol h–1 mg–1 protein. A protein extract from yeast (pYES-lacZ) was assayed as a negative control. ND, Not detectable. The minimum detectable activity was 10 pmol h–1 mg–1 protein. Values are means and se from triplicate assays.
| Methyl Acceptor Substrate (10 mM) | pYES-NMTase | pYES-lacZ |
|---|---|---|
| β-Ala | 100 | ND |
| N-Methyl β-Ala | 61.4 ± 0.34 | ND |
| N,N-Dimethyl β-Ala | 19.8 ± 0.22 | ND |
| β-Alanyl Gly | 0.39 ± 0.03 | 0.31 ± 0.01 |
| DL-β-Aminoisobutryic acid | 2.01 ± 0.13 | 0.31 ± 0.01 |
| L-Ala | 0.47 ± 0.12 | 0.21 ± 0.08 |
| L-Pro | ND | 0.17 ± 0.04 |
| trans-4-Hydroxy L-Pro | ND | ND |
| Gly | 1.77 ± 0.04 | 0.9 ± 0.1 |
| Putrescine | 1.36 ± 0.11 | 1.61 ± 0.12 |
| γ-Amino-n-butyric acid | ND | 1.15 ± 0.04 |
| N-Methyl DL-Ala | 0.65 ± 0.09 | 0.41 ± 0.02 |
| N,N-Dimethyl Gly | ND | ND |