Characterization and substrate specificity of fumarylacetoacetate fumarylhydrolase

Publisher Website
Google Scholar
Abstract
The MW of fumarylacetoacetate fumarylhydrolase [beef liver] (EC 3.7.1.2) is 86,000 .+-. 10,000, as determined by gel filtration. The enzyme appears to be a dimer with a monomer MW of 38,000-43,000, as determined by gel electrophoresis, gel filtration in guanidine-hydrochloride and ultracentrifugation. The subunits appear to be identical, as only 1 band is seen in gel electrophoresis, only 1 protein peak is detected in gel filtration in guanidine-hydrochloride and only 1 amino-terminal amino acid (proline) is detected. Three free sulfhydryl groups/denatured monomer are detected by reaction with 5,5''-dithiobis(2-nitrobenzoic acid), while for the active enzyme only 2 sulfhydryl groups react with this reagent. The extinction coefficients at 260 and 280 nm, the amino acid composition and the isoelectric point (6.7) of the enzyme are also reported. The enzyme catalyzes the hydrolysis of six 2,4-diketo acids and three 3,5-diketo acids tested. The Km of the substrates is similar but V varies by a factor of 120. The pH optimum is 7.3. The enzyme did not catalyze the hydrolysis of a number of esters tested.

This publication has 10 references indexed in Scilit: