Maleylacetoacetate (MAA)

4-Maleylacetoacetate is an intermediate in the metabolism of tyrosine.An intermediate in l-phenylalanine and l-tyrosine catabolism; accumulates in certain inherited disorders of tyrosine metabolism. Maleylacetoacetate cis,trans-isomerase, an enzyme that catalyses the reversible conversion of maleylacetoacetate to 4-fumarylacetoacetate; an enzyme that participates in l-tyrosine catabolism; a deficiency of this enzyme is associated with tyrosinaemia type IB.

Maleylacetoacetate isomerase belongs to the family of isomerases, specifically cis-trans isomerases. The systematic name of this enzyme class is 4-maleylacetoacetate cis-trans-isomerase. Other names in common use include maleylacetoacetic isomerase, maleylacetone isomerase, and maleylacetone cis-trans-isomerase. This enzyme participates in tyrosine metabolism and styrene degradation.