*4.3. Purification and Identification of Cytoprotective Peptides*

Blue mussel hydrolysates were eluted at 1.0 mL/min rate over Sephadex G-25 column (3.0 × 90 cm), then every 5 min the eluate was collected. Fractions with cytoprotective activity were separated using HPLC equipped with C18 column at 2.0 mL/min flow rate (Hypersil Gold, 250 × 10 mm, 5 μm, Thermo Scientific, Pittsburgh, PA, USA). A linear gradient elution was carried out using acetonitrile, as mentioned in a previous publication [24]. Q-TOF LC-MS/MS coupled with an ESI source (maXis-HD™, Bruker Daltonics, Bremen, Germany) was used to perform peptide identification, and subsequently MS/MS spectrometry was used in peptide sequencing (Biotools 3.2, Bruker Daltonics, Bremen, Germany) [18]. The synthesized peptides were ordered from Biostem (Ansan, Korea). HPLC-MS/MS was used to check the purity of the synthesized peptides (over 96% purity).
