title: Isolation and characterization of a fatty acyl esterase from rat lung.
abstract: In an effort to facilitate studies of the reaction involved in the removal of fatty acids from acyl proteins, we have synthesized an octanoic acid ester of doubly blocked serine, specifically octanoyl N-carbobenzoxy-L-serine-benzyl ester (octanoyl boc-serine), and used it as a substrate to guide the purification of an esterase from rat lung. The esterase was purified 228-fold by column chromatography on DE-52 cellulose, hydroxylapatite, octyl-Sepharose, and concanavalin A-Sepharose and by HPLC gel filtration. The final enzyme preparation ran as a single 77,000-Da band when subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and exhibited a single symmetrical peak (sedimentation coefficient, 4.5 S) when centrifuged through a sucrose density gradient (empirical Mr, 63,000). The esterase is an acidic protein, pI 4.1, and is very active against p-nitrophenyl esters comprised of C4-C14 fatty acids; the highest specific activity (26.5 mumol/min/mg) was obtained using p-nitrophenyl caprylate as substrate. The pH optimum of the lung esterase is near 8.0 and the activity on octanoyl boc-serine is maximum when 0.3% (w/v) Myrj-52 is included in the assay medium. The activity of the esterase is not dependent on calcium ions. The enzyme does not remove acyl groups from the G-protein of vesicular stomatitis virus or the proteolipid of bovine brain. The possible role of the esterase in the metabolism of acylated proteins is considered.
authors: Department of Microbiology, Biochemistry, and Molecular Biology, School of Medicine, University of Pittsburgh, Pennsylvania 15261.
authors: A
authors: A
authors: Basu
authors: R H
authors: RH
authors: Glew
authors: R W
authors: RW
authors: Evans
authors: G
authors: G
authors: Bandik
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D004950:Esterases / Q000302:isolation & purification*; D005227:Fatty Acids / Q000378:metabolism*; D006358:Hot Temperature; D006801:Humans; D007231:Infant, Newborn; D007526:Isoelectric Point; D008168:Lung / Q000201:enzymology*; D051381:Rats; D013379:Substrate Specificity
chemical_list: D005227:Fatty Acids; D004950:Esterases