RNA NAD-Cap (NMN-Forming) Hydrolase Activity

Catalysis of the reaction: a 5'-end NAD(+)-phospho-ribonucleoside in mRNA + H2O = a 5'-end phospho-adenosine-phospho-ribonucleoside in mRNA + beta-nicotinamide D-ribonucleotide + 2 H(+).