Purification Of Tellurium-containing Phycobiliprotein And Antioxidant Activities Of Enzymatic Digested Peptides Of Phycocyanin

HA chromatographic method for seperation and purification of Te-PC and Te-APC from tellurium-enriched S. platensis was described in this study. The optimal enzymolysis method for PC and the antioxidant activities of the digested products were investigated. Moreover, we also tried to separate the fractions from the digested products. Several meanful and important results were obtained.1. Te-PC and Te-APC with the purity raio of 5.59 (A616/A280) and 5.16 (A652/A280) were obtained by HA Chromatography, and their total Te concentrations were 611.1 and 625.3μg·g-1 protein, respectivily.2. The purities of Te-PC and Te-APC were further characterized by UV-Vis, fluorescence spectrometry and SDS-PAGE. Peptide mass fingerprint (PMF) by using MALDI-TOF-TOF mass spectrometry was employed to identifyαandβsubunits separated by SDS-PAGE. The results showed that incorporation of Te into PC and APC did not affect the identification of the subunits.3. The antioxidant activities of Te-PC and Te-APC were evaluated by ABTS·+ free radical scavenging assay. The results indicated that Te-PC exhibits stronger antioxidant acivity than PC and APC. Te-PC effectively inhibited the formation of ABTS-+free radicals in a time-and dose-dependent manner.4. Purified PC was enzymatically digested by 5 different proteases to produce bioactive peptides. We found that the treatment with trypsin led to the highest hydrolysis degree and the strongest antioxidant activities of the digested peptides. The 50% ABTS·+ scavenging concentration (SC50) of Peptide-Trypsin was 5 and 3 times of PC and Te-PC whole proteins, respectively.5. DNA scission prevention assay by using pBR322 plasmid DNA showed that Peptide-Trypsin exihibited dose-dependent protective effects on AAPH-induced DNA damage.6. Several fractions were seperated from Peptide-Trypsin by DEAE-Sepharose chromatography, with most of the digested peptides accumulated in the first fraction.