title: Penaeus vannamei isotrypsins: purification and characterization.
abstract: Three isotrypsins from digestive gland of Penaeus vannamei were purified and characterized by molecular, biochemical and kinetic parameters. Purified isotrypsins A, B, and C are glycoproteins with molecular masses between 30.2 and 32.9 kDa, and, therefore similar to other trypsins. The isoelectric points are anionic and different among the three isotrypsins: pH 3.5 for isotrypsin A, pH 3.0 for isotrypsin B, and pH 4.5 for isotrypsin C. Differences in the NH(2)-terminal amino acid sequences allowed us to define three different protein entities that match isotrypsins previously deduced by cDNA. Isoform C has higher physiological efficiency and specific activity, lower K(m), and requires higher concentrations of Ca(+2) to reach the same activity as the other two isotrypsins.
authors.affiliation: Laboratorio de Bioquímica, Centro de Investigaciones Biológicas del Noroeste. Mar Bermejo No. 195, Col. Playa Palo de Santa Rita, La Paz B.C.S. 23090, Mexico.
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Sainz
authors.forename: Fernando L
authors.initials: FL
authors.lastname: García-Carreño
authors.forename: Patricia
authors.initials: P
authors.lastname: Hernández-Cortés
mesh_terms: D000818:Animals; D004795:Enzyme Stability; D005088:Exocrine Glands / Q000201:enzymology; D006031:Glycosylation; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D007527:Isoenzymes; D007700:Kinetics; D033561:Penaeidae / Q000201:enzymology*; D013696:Temperature; D014357:Trypsin / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*
chemical_list: D007527:Isoenzymes; D014357:Trypsin