title: Purification and characterization of pepsins A1 and A2 from the Antarctic rock cod Trematomus bernacchii.
abstract: The Antarctic notothenioid Trematomus bernacchii (rock cod) lives at a constant mean temperature of -1.9 degrees C. Gastric digestion under these conditions relies on the proteolytic activity of aspartic proteases such as pepsin. To understand the molecular mechanisms of Antarctic fish pepsins, T. bernacchii pepsins A1 and A2 were cloned, overexpressed in Escherichia coli, purified and characterized with a number of biochemical and biophysical methods. The properties of these two Antarctic isoenzymes were compared to those of porcine pepsin and found to be unique in a number of ways. Fish pepsins were found to be more temperature sensitive, generally less active at lower pH and more sensitive to inhibition by pepstatin than their mesophilic counterparts. The specificity of Antarctic fish pepsins was similar but not identical to that of pig pepsin, probably owing to changes in the sequence of fish enzymes near the active site. Gene duplication of Antarctic rock cod pepsins is the likely mechanism for adaptation to the harsh temperature environment in which these enzymes must function.
authors.affiliation: Department of Chemistry & Chemical Biology and The Barnett Institute for Chemical & Biological Analysis, Northeastern University, Boston, MA, USA.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Brier
authors.forename: Giovanna
authors.initials: G
authors.lastname: Maria
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Carginale
authors.forename: Antonio
authors.initials: A
authors.lastname: Capasso
authors.forename: Yan
authors.initials: Y
authors.lastname: Wu
authors.forename: Robert M
authors.initials: RM
authors.lastname: Taylor
authors.forename: Nicholas B
authors.initials: NB
authors.lastname: Borotto
authors.forename: Clemente
authors.initials: C
authors.lastname: Capasso
authors.forename: John R
authors.initials: JR
authors.lastname: Engen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000864:Antarctic Regions; D001665:Binding Sites; D003001:Cloning, Molecular; D004792:Enzyme Precursors / Q000378:metabolism; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics; D005753:Gastric Mucosa / Q000201:enzymology; D006863:Hydrogen-Ion Concentration; D002479:Inclusion Bodies / Q000378:metabolism; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010434:Pepsin A / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D010436:Pepstatins / Q000494:pharmacology; D010473:Perciformes / Q000235:genetics / Q000378:metabolism*; D011480:Protease Inhibitors / Q000494:pharmacology; D011485:Protein Binding; D017510:Protein Folding; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012995:Solubility; D013379:Substrate Specificity; D013552:Swine; D013696:Temperature
chemical_list: D004792:Enzyme Precursors; D007527:Isoenzymes; D010436:Pepstatins; D011480:Protease Inhibitors; D011994:Recombinant Proteins; D010434:Pepsin A; C031375:pepstatin