Catalysis of the hydrolysis of a 5' tyrosyl-RNA phosphodiester bond between a protein and RNA. In picornaviruses, this covalent bond connects VPg, a viral-encoded protein essential for RNA replication, to the 5' end of all nascent picornavirus genomes; it is cleaved from viral RNA prior to its engaging in protein synthesis.
Source:
GOC:sp,
GOC:bf,
PMID:22908287,
PMID:21408223