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Collagen, a major structural protein of the ECM, is known for its high cell adherence capacity. This study was conducted to identify regions in collagen that harbour such bioactivity. Collagen from tendon was hydrolysed and the peptides fractionated using ion-exchange chromatography (IEC). Isolated peptide fractions were coated onto disposable dishes and screened for cell adherence and proliferative abilities. Active IEC fractions were further purified by chromatography, and two peptides, C2 and E1 with cell adhesion ability, were isolated. A cell adhesion assay done with different amounts of C2 coated onto disposable dishes revealed the maximum adhesion to be 94.6%, compared with 80% for collagen coated dishes and an optimum peptide coating density of 0.507 nmoles per [cm.sup.2] area of the dish. Growth of cells on C2, collagen, and E1 revealed a similar pattern and a reduction in the doubling time compared with cells grown on uncoated dishes. C2 had a mass of 2.046 kDa with 22 residues, and sequence analysis revealed a higher percentage occurrence of hydrophilic residues compared with other regions in collagen. Docking studies revealed GDDGEA in C2 as the probable site of interaction with integrins a2|31 and a101, and stability studies proved C2 to be mostly protease-resistant. Key words: collagen peptides, chromatography, cryptic peptides, cell adhesion. Le collagene, une proteine structurale importante de la matrice extracellulaire, est connue pour sa capacite d'adherence cellulaire elevee. Cette etude a ete realisee afin d'identifier les regions du collagene qui presentent une telle activite biologique. Du collagene de tendon a ete hydrolyse et les peptides ont ete fractionnes a l'aide d'une chromatographie echangeuse d'ions (CEI). Les fractions peptidiques isolees ont ete adsorbees sur des plaques jetables et criblees au plan de leur capacite a promouvoir l'adherence et la proliferation cellulaires. Les fractions de la CEI actives ont ete davantage purifiees par chromatographie et deux peptides, C2 et E1, possedant des capacites d'adherence cellulaire ont ete isoles. Des mesures d'adhesion cellulaire realisees avec differentes quantites de C2 adsorbees sur des plaques jetables ont revele que l'adhesion maximale etait de 94.6 % comparativement a 80 % pour les plaques enrobees de collagene et une densite optimale de peptide de 0.507 nmoles par [cm.sup.2] de surface de plaque. L'analyse de la croissance cellulaire sur C2, collagene et E1 a revele des patrons similaires et une reduction du temps de doublement comparativement aux cellules cultivees sur des plaques non enrobees. C2 possedait une masse de 2.046 kDa et 22 residus, et l'analyse de sequence a revele un pourcentage d'occurrence de residus hydrophiles plus eleve comparativement aux autres regions du collagene. Des etudes d'ancrage ont revele que la sequence GDDGEA de C2 etait probablement le site d'interaction avec les integrines a2|31 et a101, et des etudes de stabilite ont prouve que C2 etait pratiquement resistant aux proteases. [Traduit par la Redaction] Mots-cles: peptides du collagene, chromatographie, peptides cryptiques, adhesion cellulaire., Introduction The ECM is an intricate three-dimensional network composed of fibrous proteins and proteoglycans surrounding the cells in a tissue (Huxley-Jones et al. 2007). Collagen, a major component of the [...]

Aim: To investigate the immunomodulatory effects of the protein hydrolysate from Porphyra yezoensis. Objectives: In this study, the in vitro immunomodulatory effects of protein hydrolysate of Porphyra yezoensis was studied by assay of phagocytosis and Nitric oxide production in RAW 264.7 macrophages and DTH (Delayed type hypersensitivity), NBT (Nitroblue tetrazolium) and Neutrophil adhesion assay in mice. Results: Hydrolysate treatment was found to be non-toxic in both in vitro and in vivo models. In vitro results suggested that hydrolysate could enhance the phagocytic activity and also inhibit the production of nitric oxide. Oral administration of hydrolysate (500 mg/kg) evoked an increase in the percent neutrophil adhesion to nylon fibers as well as potentiated the DTH reaction induced by SRBC (Sheep red blood cells). A phagocytic response was observed with significant changes in formation of formazan crystals. Conclusion: The results indicated that enzymatic hydrolysate from P. yezoensis could enhance the cell mediated immune response. Thus, the Nori protein hydrolysate could be explored as a possible natural immune stimulant to be used as nutraceuticals. [ABSTRACT FROM AUTHOR]