A nucleotidase is a hydrolytic enzyme that catalyzes the hydrolysis of a nucleotide into a nucleoside and a phosphate. A nucleotidase is a hydrolytic enzyme that catalyzes the hydrolysis of a nucleotide into a nucleoside and a phosphate. For example, it converts adenosine monophosphate to adenosine, and guanosine monophosphate to guanosine. Nucleotidases have an important function in digestion in that they break down consumed nucleic acids.