Table 2. Comparison of molecular properties of human and bovine milk XORs.
| Molecular property | Human | Bovine |
|---|---|---|
| Mr | 148000* | 148300* |
| Amino acid composition | ||
| Chain length | 1333 [40] | 1332 [34] |
| Identity (%) | 90 | 90 |
| Highly conserved (%) | 4.8 | 4.8 |
| Semi-conserved (%) | 4.0 | 4.0 |
| Unconserved (%) | 1.2 | 1.2 |
| Xanthine oxidase activity (μmol·min−1·mg−1) | 0.09* | 1.4* |
| NADH oxidase activity (μmol·min−1·mg−1) | 0.33 [13] | 0.28 [13] |
| FAD content (mol/subunit) | 1* | 1* |
| Mo content (atom/subunit) | 0.04* | 0.61* |
| Molybdopterin content (mol/subunit) | 0.09* | 0.62* |
| Mo=S (sulpho content) (% theoretical based on available Mo) | 40–50* | 45*† |
| FeS centres | See text | See text |
* The present study.
† Based on Mo content and activity.