Maleylpyruvate isomerase () is an enzyme that catalyzes the chemical reaction
The enzyme has one substrate, 3-maleylpyruvic acid, which it converts to its geometric isomer, 3-fumarylpyruvic acid.
This enzyme belongs to the family of isomerases, specifically cis-trans isomerases. The systematic name of this enzyme class is 3-maleylpyruvate cis-trans-isomerase. This enzyme participates in tyrosine metabolism.
As of late 2007, two structures have been solved for this class of enzymes, with PDB accession codes and .