Preparation and specification
| Appearance | Yellow amorphous powder, lyophilized |
| Protein purity | ≥90% (from SDS-PAGE) |
| Activity | ≥8 U/mg solid |
| Glucose-6-phosphate dehydrogenase | ≤0.01% |
| Lactate dehydrogenase | ≤0.01% |
Properties
| EC number | 4.2.1.22 (Recombinant from microorganism) | |
| Molecular weight | 51 kDa (SDS-PAGE) | |
| Isoelectric point | 5.4 | |
| Optimum pH | 7.0-8.0 | |
| Michaelis constants | 8.0 ×10-4 M (L-Serine), 1.6 ×10-4 M(L-Homocysteine) | |
| Inhibitors | Not inhibited by NaN3 | |
| Optimum pH | 8.0 | Fig. 1 |
| Optimum temperature | 40 ℃ | Fig. 2 |
| pH stability | pH 6.0-10.0 (25℃, 16 h) | Fig. 3 |
| Thermal stability | Below 45 ℃ (pH 8.0, 30 min) | Fig. 4 |
| Storage stability | At least one year at -25～-15 ℃ | Fig. 5 |
| Stabilizers | Triton X-100 | |
Applications
This enzyme is useful for enzymatic determination of L-homocysteine when coupled with CBS and LDH in clinical analysis.
Unit definition
One unit (U) is defined as the amount of enzyme which consumes 1 μmol of NADH per min under the conditions described below.
