The suffix -ase is used in biochemistry to form names of enzymes. The most common way to name enzymes is to add this suffix onto the end of the substrate, e.g. an enzyme that breaks down peroxides may be called peroxidase; the enzyme that produces telomeres is called telomerase. Sometimes enzymes are named for the function they perform, rather than substrate, e.g. the enzyme that polymerizes DNA into strands is called polymerase; see also reverse transcriptase.
This suffix was likeliest extracted from the name of diastase, which was named from Greek διαστασις, "separation".