ribosylation

(noun)

The attachment of a ribose or ribosyl group to a molecule, especially to a polypeptide or protein

Related Terms

Examples of ribosylation in the following topics:

  • Diphtheria

    • It does this by catalyzing ADP-ribosylation of elongation factor EF-2—a protein that is essential to the translation step of protein synthesis.
    • This ADP-ribosylation involves the transfer of an ADP-ribose from NAD+ to a diphthamide (a modified histidine) residue within the EF-2 protein.
    • Since EF-2 is needed for the moving of tRNA from the A-site to the P-site of the ribosome during protein translation, ADP-ribosylation of EF-2 prevents protein synthesis.
    • ADP-ribosylation of EF-2 is reversed by giving high doses of nicotinamide (a form of vitamin B3), since this is one of the reaction's end-products, thus high amounts will drive the reaction in the opposite direction counteracting the toxin.

  • Purine and Pyrimidine Synthesis

    • A key regulatory step is the production of 5-phospho-α-D-ribosyl 1-pyrophosphate (PRPP) by PRPP synthetase, which is activated by inorganic phosphate and inactivated by purine ribonucleotides.