| in order to conserve energy | 6 | purpose |
| at their active sites | 5 | location |
| heavily | 3 | degree |
| enzyme → contain → iron | 18 |
| enzyme → require → iron | 9 |
| enzyme → rely on → iron | 5 |
| enzyme → use → iron | 4 |
| enzyme → employ → iron | 3 |
| negative | neutral | positive |
| 0.074 | 0.830 | 0.095 |
| Raw frequency | 39 |
| Normalized frequency | 0.467 |
| Modifier score | 0.700 |
| Perplexity | 161.761 |