title: Purification and some properties of maleylpyruvate hydrolase and fumarylpyruvate hydrolase from Pseudomonas alcaligenes.
abstract: Hydrolysis of the gentisate ring-cleavage product, maleylpyruvate (cis-2,4-diketohept-5-enedioic acid), was shown to be catalyzed by an enzyme, maleylpyruvate hydrolase 11, in Pseudomonas alcaligenes (P25X1) after growth with 3-hydroxybenzoate. This activity was separated from fumarylpyruvate hydrolase activity during the course of its purification which accomplished an approximately 50-fold increase in specific activity. An apparent molecular weight of 77,000 was assigned on the basis of Sephadex G-200 chromatography. Despite the presence of up to three similarly migrating bands of protein on polyacrylamide-gel electrophoresis of the purified enzyme, at least two of these bands possessed maleylpyruvate hydrolase activity. Electrophoresis on sodium dodecyl sulfate-polyacrylamide before and after reduction with mercaptoethanol gave a principal band of molecular weight of 33,000 (and a minor band of molecular weight 50,000). A number of substituted maleylpyruvates also served as substrates for maleylpyruvate hydrolase 11, but maleylacetoacetate and fumarylpyruvate were not attacked. Fumarylpyruvate hydrolase was purified approximately 40-fold to give a single band on polyacrylamide gels and with an apparent molecular weight of 73,000 by Sephadex G-200 chromatography. Upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis before or after reduction with mercaptoethanol, a subunit molecular weight of 25,000 was obtained. Neither maleylpyruvate nor fumarylacetoacetate served as substrates for fumarylpyruvate hydrolase. The activities of both maleyl- and fumarylpyruvate hydrolases were stimulated by Mn(2+) ions. Reasons are discussed for the presence of both enzyme activities, one of which appears to be redundant.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D001426:Bacterial Proteins; D006863:Hydrogen-Ion Concentration; D006867:Hydrolases / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D008345:Manganese / Q000494:pharmacology; D008970:Molecular Weight; D011549:Pseudomonas / Q000201:enzymology*
chemical_list: D000596:Amino Acids; D001426:Bacterial Proteins; D008345:Manganese; D006867:Hydrolases; C026249:fumarylpyruvate hydrolase; C026248:maleylpyruvate hydrolase