RNA triphosphatase

• the metal-dependent family. Yeast, protozoan, and viral RTPases require a metal co-factor for their activity, which is most often either Mg²⁺ or Mn²⁺. This class of enzymes is also able to hydrolyze free nucleoside triphosphates in the presence of either Mn²⁺ or Co²⁺.
• the metal-independent family. These groups do not require metals for their activity, and some enzymes have been shown to be inactivated in the presence of metal ions. These enzymes are very much similar to protein tyrosine phosphatases in their structure and mechanism. This family includes RTPases from mammals, plants, and other higher eukaryotes, and is structurally and mechanistically different from the metal-dependent RTPase family.