title: Purification and partial characterization of rat intestinal cefuroxime axetil esterase.
abstract: An esterase which hydrolyses the cephalosporin antibiotic, cefuroxime axetil has been isolated from rat intestinal washings and purified. Closely related cefuroxime esters were extremely poor substrates, but p-nitrophenyl acetate and alpha-naphthyl acetate were slowly hydrolysed by the purified enzyme. Analysis by gel filtration gave an Mr = 51,000 and on SDS-polyacrylamide gel electrophoresis the esterase resolved into two main bands of Mr = 31,500 and 26,800. Analytical isoelectric focusing resolved purified esterase into multiple forms active toward alpha-naphthyl acetate, the isoelectric points of which ranged from pH 4.5 to 6.3. The esterase bound specifically to Con A-Sepharose suggesting it could be a glycoprotein. Esterase activity was unaffected by the presence of dihydroxy bile salts (1-8 mM) and inhibition studies using organophosphates and eserine salicylate have classified the enzyme as a carboxylesterase.
mesh_terms: D000818:Animals; D001647:Bile Acids and Salts / Q000494:pharmacology; D002265:Carboxylic Ester Hydrolases / Q000037:antagonists & inhibitors / Q000302:isolation & purification* / Q000378:metabolism; D002444:Cefuroxime / Q000031:analogs & derivatives* / Q000378:metabolism; D002511:Cephalosporins; D004285:Dogs; D006801:Humans; D007421:Intestine, Small / Q000201:enzymology*; D007525:Isoelectric Focusing; D007531:Isoflurophate / Q000494:pharmacology; D008297:Male; D009284:Naphthols / Q000378:metabolism; D010664:Phenylmethylsulfonyl Fluoride / Q000494:pharmacology; D010830:Physostigmine / Q000031:analogs & derivatives / Q000494:pharmacology; D051381:Rats / Q000378:metabolism*; D013045:Species Specificity; D013379:Substrate Specificity
chemical_list: D001647:Bile Acids and Salts; D002511:Cephalosporins; D009284:Naphthols; D007531:Isoflurophate; C026718:physostigmine salicylate; D010664:Phenylmethylsulfonyl Fluoride; C027876:alpha-naphthyl acetate; D010830:Physostigmine; D002265:Carboxylic Ester Hydrolases; C053181:cefuroxime axetil esterase; D002444:Cefuroxime; C040738:cefuroxime axetil