Purification and characterization of pepsins A1 and A2 from the Antarctic rock cod Trematomus bernacchii

• Published in: FEBS Journal
• Main Authors: Brier, Sébastien, Maria, Giovanna, Carginale, Vincenzo, Capasso, Antonio, Wu, Yan, Taylor, Robert M., Borotto, Nicholas B., Capasso, Clemente, Engen, John R.
• Format: Text
• Language: English
• Published: 2007
• Subjects: Article; Antarctic; The Antarctic; Antarc*
• Online Access: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2533623; http://www.ncbi.nlm.nih.gov/pubmed/17976195; https://doi.org/10.1111/j.1742-4658.2007.06136.x

The Antarctic notothenioid Trematomus bernacchii (rock cod) lives at a constant mean temperature of −1.9 °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 E. coli, purified and characterized with a number of biochemical and biophysical methods. The properties of these two Antarctic isoenzymes were compared to 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 the mesophilic counterpart. The specificity of Antarctic fish pepsins was similar but not identical to pig pepsin, likely 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.