title: Digestion by pepsin releases biologically active chromopeptides from C-phycocyanin, a blue-colored biliprotein of microalga Spirulina.
abstract: C-phycocyanin, the major protein of cyanobacteria Spirulina, possesses significant antioxidant, anti-cancer, anti-inflammatory and immunomodulatory effects, ascribed to covalently attached linear tetrapyrrole chromophore phycocyanobilin. There are no literature data about structure and biological activities of released peptides with bound chromophore in C-phycocyanin digest. This study aims to identify chromopeptides obtained after pepsin digestion of C-phycocyanin and to examine their bioactivities. C-phycocyanin is rapidly digested by pepsin in simulated gastric fluid. The structure of released chromopeptides was analyzed by high resolution tandem mass spectrometry and peptides varying in size from 2 to 13 amino acid residues were identified in both subunits of C-phycocyanin. Following separation by HPLC, chromopeptides were analyzed for potential bioactivities. It was shown that all five chromopeptide fractions have significant antioxidant and metal-chelating activities and show cytotoxic effect on human cervical adenocarcinoma and epithelial colonic cancer cell lines. In addition, chromopeptides protect human erythrocytes from free radical-induced hemolysis in antioxidative capacity-dependant manner. There was a positive correlation between antioxidative potency and other biological activities of chromopeptides. Digestion by pepsin releases biologically active chromopeptides from C-phycocyanin whose activity is mostly related to the antioxidative potency provided by chromophore.
authors.affiliation: Center of Excellence for Molecular Food Sciences, University of Belgrade - Faculty of Chemistry, Studentski trg 12-16, 11000 Belgrade, Serbia.
authors.forename: Simeon L
authors.initials: SL
authors.lastname: Minic
authors.affiliation: Center of Excellence for Molecular Food Sciences, University of Belgrade - Faculty of Chemistry, Studentski trg 12-16, 11000 Belgrade, Serbia.
authors.forename: Dragana
authors.initials: D
authors.lastname: Stanic-Vucinic
authors.affiliation: Center of Excellence for Molecular Food Sciences, University of Belgrade - Faculty of Chemistry, Studentski trg 12-16, 11000 Belgrade, Serbia.
authors.forename: Jelena
authors.initials: J
authors.lastname: Mihailovic
authors.affiliation: Center of Excellence for Molecular Food Sciences, University of Belgrade - Faculty of Chemistry, Studentski trg 12-16, 11000 Belgrade, Serbia.
authors.forename: Maja
authors.initials: M
authors.lastname: Krstic
authors.affiliation: Center of Excellence for Molecular Food Sciences, University of Belgrade - Faculty of Chemistry, Studentski trg 12-16, 11000 Belgrade, Serbia; Department of Biochemistry, University of Belgrade - Faculty of Chemistry, Studentski trg 12-16, 11000 Belgrade, Serbia.
authors.forename: Milan R
authors.initials: MR
authors.lastname: Nikolic
authors.affiliation: Center of Excellence for Molecular Food Sciences, University of Belgrade - Faculty of Chemistry, Studentski trg 12-16, 11000 Belgrade, Serbia; Department of Biochemistry, University of Belgrade - Faculty of Chemistry, Studentski trg 12-16, 11000 Belgrade, Serbia. Electronic address: tcirkov@chem.bg.ac.rs.
authors.forename: Tanja
authors.initials: T
authors.lastname: Cirkovic Velickovic
mesh_terms: D000975:Antioxidants; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D003110:Colonic Neoplasms / Q000188:drug therapy; D003116:Color; D004912:Erythrocytes / Q000187:drug effects; D005260:Female; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D010434:Pepsin A / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use; D010798:Phycocyanin / Q000378:metabolism*; D053545:Spirulina / Q000737:chemistry*; D002583:Uterine Cervical Neoplasms / Q000188:drug therapy
chemical_list: D000975:Antioxidants; D010455:Peptides; D010798:Phycocyanin; D010434:Pepsin A
keywords: Bioactivity; C-phycocyanin; Digestibility; Peptides; Phycocyanobilin