In enzymology, a m7G(5')pppN diphosphatase or m7G(5')pppN pyrophosphatase () is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are 7-methylguanosine 5'-triphospho-5'-polynucleotide and H<sub>2</sub>O, whereas its two products are 7-methylguanosine 5'-phosphate and 5'-diphospho-polyribonucleotide.
This is the enzyme involved in the processing of amphetamines of the cathinone group, including mephedrone and khat.
This enzyme belongs to the family of hydrolases, specifically those acting on acid anhydrides in phosphorus-containing anhydrides. The systematic name of this enzyme class is 7-methylguanosine-5'-triphospho-5'-polynucleotide 7-methylguanosine-5'-phosphohydrolase.
Another name in common use is decapase because this enzyme removes the N7-methylguanosine 5-phosphate cap from an mRNA. The process of mRNA decapping controls eukaryotic mRNA degradation.