title: Purification and properties of a carboxylesterase from the liver of tiger shark (Galeocerdo cuvier).
abstract: A procedure is described for the purification of a carboxylesterase from shark liver, using a chloroform-acetone powder prepared from the liver as the starting material. The yield of purified enzyme is approximately 50 mg from 530 g of chloroform-acetone powder. The preparation is electrophoretically homogeneous. Active-site titrations with paraoxon gave an equivalent weight of approximately 83 000. The molecular weight, found from sedimentation equilibrium experiments, is approximately 80 000. There is no evidence of any association or dissociation of this species. The enzyme shows a marked preference for aryl esters over alkyl esters, in contrast to other carboxylesterases so far studied. The amino acid composition of the purified enzyme is reported.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002265:Carboxylic Ester Hydrolases / Q000302:isolation & purification / Q000378:metabolism*; D002729:Chloromercuribenzoates / Q000494:pharmacology; D004237:Diuron / Q000494:pharmacology; D007460:Iodoacetamide / Q000494:pharmacology; D007461:Iodoacetates / Q000494:pharmacology; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008433:Mathematics; D008970:Molecular Weight; D012754:Sharks / Q000378:metabolism*; D013045:Species Specificity
chemical_list: D000596:Amino Acids; D002729:Chloromercuribenzoates; D007461:Iodoacetates; D004237:Diuron; D002265:Carboxylic Ester Hydrolases; D007460:Iodoacetamide