From Wikipedia, the free encyclopedia
Jump to: navigation, search
CAS number 75645-22-6 YesY
PubChem 6438375
ChemSpider 4942856 YesY
Jmol-3D images Image 1
Image 2
Molecular formula C13H23N5O3
Molar mass 297.35 g mol−1
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
Infobox references

Diphthamide is a modified histidine amino acid found in eukaryotic elongation factor 2 (eEF-2).

It is usually found at position H715 in mammalian eEF2 (H699 in yeast). This residue is modified by the protein encoded by the DPH1 (OVCA1) gene. Dph1 knockout mice are inviable while heterozygotes develop diverse types of carcinomas and sarcomas. In humans, DH1 is frequently found mutated in ovarian cancer. Loss of heterozygosity has taken place in 50% of benign tumours, and 90% of end-stage ovarian tumours.

It is ADP-ribosylated by diphtheria toxin, hence the name, which renders the elongation factor inactive.