m(7)GTP-Sepharose is routinely used for cap binding protein isolation. Here we present the synthesis of a new affinity resin containing a mononucleotide cap analog resistant to hydrolysis by DcpS. The resin has been designed in order to identify and purify Arabidopsis thaliana DcpS and other pyrophosphatases. The binding efficiency of the new resin to eIF4E protein was compared with standard m(7)GTP-Sepharose. The utility of non-hydrolysable resin was demonstrated on yeast extract.