title: Purification of a chymotrypsin-like enzyme present on adult Schistosoma mansoni worms from infected mice and its characterization as a host carboxylesterase.
abstract: A serine protease-like enzyme found in detergent extracts of Schistosoma mansoni adult worms perfused from infected mice has been purified from mouse blood and further characterized. The enzyme is approximately 85 kDa and hydrolyses N-acetyl-DL-phenylalanine β-naphthyl-ester, a chromogenic substrate for chymotrypsin-like enzymes. The enzyme from S. mansoni worms appears to be antigenically and enzymatically similar to a molecule that is present in normal mouse blood and so is seemingly host-derived. The enzyme was partially purified by depleting normal mouse serum of albumin using sodium chloride and cold ethanol, followed by repeated rounds of purification by one-dimensional sodium dodecyl sulphate polyacrylamide gel electrophoresis. The purified material was subjected to tandem mass spectrometry and its derived peptides found to belong to mouse carboxylesterase 1C. Its ability to hydrolyse α- or β-naphthyl acetates, which are general esterase substrates, has been confirmed. A similar carboxylesterase was purified and characterized from rat blood. Additional evidence to support identification of the enzyme as a carboxylesterase has been provided. Possible roles of the enzyme in the mouse host-parasite relationship could be to ease the passage of worms through the host's blood vessels and/or in immune evasion.
authors.affiliation: School of Life Sciences, University Park, University of Nottingham,Nottinghamshire NG7 2RD,UK.
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Igetei
authors.affiliation: School of Biosciences, Sutton Bonington Campus, University of NottinghamLE12 5RD,UK.
authors.forename: Susan
authors.initials: S
authors.lastname: Liddell
authors.affiliation: School of Life Sciences, University Park, University of Nottingham,Nottinghamshire NG7 2RD,UK.
authors.forename: Marwa
authors.initials: M
authors.lastname: El-Faham
authors.affiliation: School of Life Sciences, University Park, University of Nottingham,Nottinghamshire NG7 2RD,UK.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Doenhoff
mesh_terms: D000818:Animals; D001700:Biomphalaria; D043182:Carboxylesterase / Q000097:blood / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D006868:Hydrolysis; D005779:Immunodiffusion; D047468:Immunoprecipitation; D051379:Mice; D008970:Molecular Weight; D010649:Phenylalanine / Q000031:analogs & derivatives / Q000378:metabolism; D011817:Rabbits; D051381:Rats; D012550:Schistosoma mansoni / Q000201:enzymology*; D012709:Serum Albumin / Q000378:metabolism; D053719:Tandem Mass Spectrometry
chemical_list: D012709:Serum Albumin; C013791:N-acetylphenylalanine beta-naphthyl ester; D010649:Phenylalanine; D043182:Carboxylesterase
keywords: Schistosoma mansoni; carboxylesterase 1C; host-derived enzyme; immune evasion; mice