| X.l. | Xenopus laevis |
|---|---|
| XA | Xanthurenic acid |
| XAC | Xanthine amine congener |
| XAFS | X-Ray Absorption Fine Structure |
| XANES | X-ray Absorption Near Edge Structure |
| XAS | X-ray Absorption Spectroscopy |
| XCI | X chromosome inactivation |
| XCIP | X chromosome inactivation pattern |
| XD | Xanthine dehydrogenase |
| XDH | Xanthine dehydrogenase |