雞精抗氧化相關之低分子量胜肽類   全文下載

Low-molecular-weight Peptides as Related to Antioxidant Properties of Chicken Essence

雞精萃取物經以抑制亞麻油酸自氧化、清除DPPH自由基、還原能力、螯合金屬離子等四種方法檢測，得知具抗氧化能力，且其活性隨濃度的增加而增強。雞精中含多量游離胺基酸，其中以牛磺酸為主要成分；低分子量胜?類含量亦甚豐，尤其含大量具抗氧化性之肌與甲肌?等雙胜?類最為特殊。以膠體過濾層析法劃分雞精萃取物分子量，可得三個胜區分物，分子量約在1400 Da之胜?的抗氧化性較900和500 Da為強，經進一步分離純化，二種具強抗氧化性之胜?被鑑定得知其胺基酸序列，分別為His-Val-Thr-Glu-Glu和Pro-Val-Pro-Ala-Glu-Gly-Val。

Different antioxidant measurements, including the inhibition of linoleic acid autoxidation, scavenging effect on α,α-diphenyl-β- picrylhydrazyl free radical, reducing power, and chelating abilities of metal ions Cu2+ and Fe2+, showed that the extract of chicken essence possessed antioxidant activities. The antioxidant activity increased with increasing concentration. Chicken essence contained a considerable amount of free amino acids, of which taurine was the predominant compound. Low-molecular-weight peptides were also present in a large quantity. An extraordinary feature was that the product contained high levels of potent antioxidants, anserine and carnosine. Three antioxidant peptide fractions of chicken essence were separated by size exclusion chromatography. The peptide with molecular weight of approximately 1400 Da possessed the strongest antioxidant activity, followed by peptides with 900 and 500 Da. Two antioxidant peptides were further isolated and identified, and their amino acid sequences were His-Val-Thr-Glu-Glu and Pro-Val- Pro-Ala-Glu-Gly-Val, respectively.