The enzyme quercitrinase (, formerly 3.2.1.66) catalyzes the following chemical reaction:
Thus, the two substrates of this enzyme are quercitrin and H<sub>2</sub>O, whereas its two products are L-rhamnose and quercetin.
This enzyme belongs to the family of hydrolases, specifically those glycosidases that hydrolyse O- and S-glycosyl compounds. The systematic name of this enzyme class is quercitrin 3-L-rhamnohydrolase.
The enzyme can be found in Aspergillus flavus. It is an enzyme in the rutin catabolic pathway.