Bio-catalysts; accelerate biochemical reactions.
Enzymes (once called “ferments”) comprise a large group of proteins that increase the reaction rates of biochemical processes sometimes as much as million-fold. They are produced by all living cells, and act both inside and outside of cells.
There are tens of thousands of different enzymes. All are highly specific, meaning that each enzyme usually catalyses just one defined biochemical reaction. The names of enzymes often end in "...ase": an "amylase" cleaves starch, a "chitinase" splits chitin.
In molecular biology, certain enzymes are tools for cleaving and rejoining the DNA, the carrier of genetic information. “Restriction enzymes” recognise defined sequences of nucleotides to cut the DNA precisely at that site. Other enzymes (ligases) can link separate strands of DNA into one, continuous piece.