Hydrolases are a broad class of enzymes that undergo one simple function. They catalyze hydrolysis, the splitting of two groups of a molecule by adding H2O.

In an aqueous environment, the presence of a hydrolase such as pyrophosphatase gives the electrostatic shove needed to allow a water molecule to donate its two hydrogens and an oxygen to separate the molecule. By donating protons, the water maintains the polarity of the overall system. The hydrolase is reusable, so once it has finished catalyzing the hydrolysis reaction, it goes about on its merry way again to catalyze another reaction.