Identification and inhibitory activity against α-thrombin of a novel anticoagulant peptide derived from oyster (Crassostrea gigas) protein

A newly discovered anticoagulant peptide was isolated, purified and identified from the pepsin hydrolysate of oyster (Crassostrea gigas) which could potently prolong the activated partial thromboplastin time and the thrombin time.

Isolation of a Bifidogenic Peptide from the Pepsin Hydrolysate of Bovine Lactoferrin

ABSTRACTLactoferrin is an iron-binding glycoprotein found in the milk of most mammals for which various biological functions have been reported, such as antimicrobial activity and bifidogenic activity. In this study, we compared the bifidogenic activity of bovine lactoferrin (bLF) and pepsin hydrolysate of bLF (bLFH), isolated bifidogenic peptide from bLFH, and investigated the bifidogenic spectra of bLF, bLFH, and its active peptide against 42 bifidobacterial strains comprising nine species. AgainstBifidobacterium breveATCC 15700T, minimal effective concentrations of bLF and bLFH were 300 and 10 μg/ml. AgainstBifidobacterium longumsubsp.infantisATCC 15697T, the minimal effective concentration of bLFH was 30 μg/ml, and bLF did not show bifidogenic activity within 300 μg/ml. As an active peptide, a heterodimer of A1-W16and L43-A48linked by a disulfide bond was isolated. Previously, this peptide was identified as having antibacterial activity. An amino acid mixture with the same composition as this peptide showed no bifidogenic activity. The strains of each species whose growth was highly promoted (>150%) by this peptide at 3.75 μM were as follows:B. breve(7 out of 7 strains [7/7]),B. longumsubsp.infantis(5/5),Bifidobacterium bifidum(2/5),B. longumsubsp.longum(1/3),Bifidobacterium adolescentis(3/6),Bifidobacterium catenulatum(1/4),Bifidobacterium pseudocatenulatum(0/4),Bifidobacterium dentium(0/5), andBifidobacterium angulatum(0/3). Growth of none of the strains was highly promoted by bLF at 3.75 μM. We demonstrated that bLFH showed stronger bifidogenic activity than natural bLF, especially against infant-representative species,B. breveandB. longumsubsp.infantis; furthermore, we isolated its active peptide. This is the first report about a bifidogenic peptide derived from bLF.

Thermal Treatment to Improve the Antioxidant Activity of Half-Fin Anchovy Pepsin Hydrolysate and Application in Beef Storage

In this study, the antioxidant activity and browning intensity of thermal products of half-fin anchovy pepsin hydrolysate (HAHp) were investigated. Thermal treatment, in particular at 121 °C, increased the 1, 1-diphenyl-2-picrylhydrazayl (DPPH) radical scavenging rates. The browning intensity ranging from 0.082 to 0.372 displayed a linear correlation (R2=0.9343) with their corresponding scavenging DPPH radical rates. During 12 days of storage at 4 °C, the antioxidant activity of ground beef meat with addition of heated HAHp (HAHp-H, 121°C for 30 min) was determined using the following assays: a pH assay, a DPPH assay and a malondialdehyde (MDA) assay. The results showed that the HAHp-H treatment significantly inhibited the pH value changes compared with the control or HAHp treatments (P < 0.05). The HAHp-H treatment remained unaffected or slightly decreased activity on scavenging DPPH radicals throughout storage. By comparison, the DPPH radical scavenging rates of control and HAHp treatments greatly decreased upon storage. The increase of MDA values of all treatments indicated that the lipid oxidation of beef meat increased with storage time, whereas, the HAHp-H treatment still had significantly lower MDA value (0.433 nmol/mg prot) than the control (1.141nmol/mg prot) and HAHp treatments (0.884 nmol/mg prot) after 12 days of storage (P < 0.05). Overall, HAHp-H could be a potent antioxidant in minimizing beef meat oxidation stored at 4 °C.