title: Speciation of iodine-containing proteins in Nori seaweed by gel electrophoresis laser ablation ICP-MS.
abstract: An analytical approach providing an insight into speciation of iodine in water insoluble fraction of edible seaweed (Nori) was developed. The seaweed, harvested in the Galician coast (Northwestern Spain), contained 67.7±1.3 μg g(-1) iodine of which 25% was water soluble and could be identifies as iodide. Extraction conditions of water insoluble residue using urea, NaOH, SDS and Triton X-100 were investigated. The protein pellets obtained in optimized conditions (after precipitation of urea extracts with acetone), were digested with trypsin and protease XIV. Size exclusion chromatography-ICP-MS of both enzymatic digests demonstrated the occurrence of iodoaminoacids putatively present in proteins. Intact proteins could be separated by gel electrophoresis after an additional extraction of the protein extract with phenol. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS PAGE) with laser ablation ICP-MS detection of (127)I indicated the presence of iodine in protein bands corresponding to molecular masses of 110 kDa, 40 kDa, 27 kDa, 20 kDa and 10 kDa. 2D IEF-SDS PAGE with laser ablation ICP-MS (127)I imaging allowed the detection of 5 iodine containing protein spots in the alkaline pI range.
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: V
authors.initials: V
authors.lastname: Romarís-Hortas
authors.affiliation: CNRS/UPPA, Laboratoire de Chimie Analytique Bio-inorganique et Environnement, UMR5254, Hélioparc, 2, Av. Angot, 64053 Pau, France.
authors.forename: J
authors.initials: J
authors.lastname: Bianga
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: A
authors.initials: A
authors.lastname: Moreda-Piñeiro
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: P
authors.initials: P
authors.lastname: Bermejo-Barrera
authors.affiliation: CNRS/UPPA, Laboratoire de Chimie Analytique Bio-inorganique et Environnement, UMR5254, Hélioparc, 2, Av. Angot, 64053 Pau, France. Electronic address: joanna.szpunar@univpau.fr.
authors.forename: J
authors.initials: J
authors.lastname: Szpunar
mesh_terms: D000096:Acetone / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D007455:Iodine / Q000032:analysis*; D007834:Lasers; D013058:Mass Spectrometry / Q000379:methods; D017830:Octoxynol / Q000737:chemistry; D010447:Peptide Hydrolases / Q000737:chemistry; D019800:Phenol / Q000737:chemistry; D010940:Plant Proteins / Q000737:chemistry*; D044664:Porphyra; D012624:Seaweed; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D012972:Sodium Hydroxide / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D014357:Trypsin / Q000737:chemistry; D014508:Urea / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D010940:Plant Proteins; D012997:Solvents; D014867:Water; D000096:Acetone; D019800:Phenol; D012967:Sodium Dodecyl Sulfate; D012972:Sodium Hydroxide; D014508:Urea; D017830:Octoxynol; D007455:Iodine; D010447:Peptide Hydrolases; D014357:Trypsin; C030732:protease IV
keywords: Gel electrophoresis; Inductively coupled plasma mass spectrometry; Iodine speciation; Laser ablation; Seaweed