title: Assessment of metals bound to marine plankton proteins and to dissolved proteins in seawater.
abstract: Studies based on laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) have been performed to assess metal bound to dissolved proteins and proteins from marine plankton after two-dimensional polyacrylamide gel electrophoresis (2D PAGE). Dissolved proteins were pre-concentrated from surface seawater (60 L) by tangential ultrafiltration with 10 kDa molecular weight cut-off (MWCO) membranes and further centrifugal ultrafiltration (10 kDa) before proteins isolation by methanol/chloroform/water precipitation. Proteins isolation from plankton was assessed after different trichloroacetic acid (TCA)/acetone and methanol washing stages, and further proteins extraction with a phenol solution. LA-ICP-MS analysis of the electrophoretic profiles obtained for dissolved proteins shows the presence of Cd, Cr, Cu, and Zn in five spots analyzed. These proteins exhibit quite similar molecular weights (within the 10-14 kDa range) and pIs (from 5.8 to 7.3). Cd, Cr, Cu, and Zn have also been found to be associated to proteins isolated from plankton samples. In this case, Cd has been found to be bound to proteins of quite different molecular weight (9, 13 and 22 kDa) and pIs (4.5, 5.2, 5.5, and 10). However, trace elements such as Cr, Cu and Zn appear to be mainly bound to plankton proteins of low molecular weight and variable pI.
authors.affiliation: Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, Avenida das Ciencias, s/n, 15782 Santiago de Compostela, Spain.
authors.forename: Natalia
authors.initials: N
authors.lastname: García-Otero
authors.forename: María Carmen
authors.initials: MC
authors.lastname: Barciela-Alonso
authors.forename: Pilar
authors.initials: P
authors.lastname: Bermejo-Barrera
authors.forename: Antonio
authors.initials: A
authors.lastname: Moreda-Piñeiro
authors.forename: María S
authors.initials: MS
authors.lastname: Jiménez
authors.forename: María T
authors.initials: MT
authors.lastname: Gómez
authors.forename: Juan R
authors.initials: JR
authors.lastname: Castillo
mesh_terms: D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D008386:Marine Biology; D013058:Mass Spectrometry; D008670:Metals / Q000378:metabolism*; D010933:Plankton / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D012623:Seawater; D014462:Ultrafiltration
chemical_list: D008670:Metals; D010940:Plant Proteins
keywords: 2D polyacrylamide gel electrophoresis; Dissolved proteins; Laser ablation inductively coupled plasma mass spectrometry; Metal-binding proteins; Phytoplankton