Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Chemical mechanism of PARylation by PARP1/2. In an initiation reaction, the ADPR moiety of the NAD+ substrate is attached to an amino acid side chain on PARP1/2. Elongation occurs wherein additional ADPRs are added to the existing ADPR, resulting in chain lengths up to 200. Branching of the PAR chains can also occur at the site indicated by an arrow. Additionally, PARP1 can simply hydrolyze NAD+ to yield free ADPR and nicotinamide in a reaction known as treadmilling.
