InterPro domain: IPR026750

Protein N-terminal asparagine amidohydrolase (NTAN1) acts on the side-chain deamidation of N-terminal asparagine residues to aspartate. It is required for the ubiquitin-dependent turnover of intracellular proteins that initiate with Met-Asn. These proteins are acetylated on the retained initiator methionine and can subsequently be modified by the removal of N-acetyl methionine by acylaminoacid hydrolase (AAH). Conversion of the resulting N-terminal asparagine to aspartate by PNAD renders the protein susceptible to arginylation, polyubiquitination and degradation as specified by the N-end rule. NTAN1 does not act on substrates with internal or C-terminal asparagines and does not act on glutamine residues in any position [ 1 , 2 ].

1. Protein NH2-terminal asparagine deamidase. Isolation and characterization of a new enzyme. J. Biol. Chem. 269, 23509-17
2. The sequence of porcine protein NH2-terminal asparagine amidohydrolase. A new component of the N-end Rule pathway. J. Biol. Chem. 270, 25-8