Guangdong Provincial Key Lab of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, 510631, China.
Sci Rep. 2022 Aug 2;12(1):13223. doi: 10.1038/s41598-022-16009-5.
Crocodiles are cultured in large numbers in Asia and other places in order to protect wild resources and meet the needs of human life. In this study, crocodile (Crocodylus siamensis) meat proteins were extracted and hydrolyzed into peptides, their antioxidant peptides were isolated and purified by silica gel chromatography and identified by LC/MS. Crocodile meat proteins were optimally extracted with water and hydrolyzed by papain based on the degree of hydrolysis and antioxidant activity. The hydrolysates were fractionated by ultrafiltration into 3 kDa, 3-30 kDa, and ≥ 30 kDa fractions. The 3 kDa fraction showed most antioxidant activity of the hydrolysates. Its active peptides were separated by silica gel column chromatography and purified by silica gel TLC, based on TLC bio-autographic assays of the activity. Four highly active peptides were identified by LC/MS as SSLTIQFVEGQFVDSYDPTIENTFTK, VPPHIY, VAPEEHPVLLTEAPLNPK, and RNGLPGPIGPAG. The identified peptides were synthesized and showed 50% free radical scavenging activities at 1.0 mg/mL, equal or higher to ascorbic acid at 0.5 mg/mL, in both DPPH and ABTS assays. The results indicated that the 3 kDa hydrolyzed peptides of crocodile meat had high antioxidant activity and the active peptides can be effectively separated and purified by silica gel column chromatography and TLC.
为了保护野生资源和满足人类生活的需要，亚洲和其他地方大量养殖鳄鱼。在本研究中，从鳄鱼（暹罗鳄）肉中提取蛋白质并水解成肽，通过硅胶层析法对其抗氧化肽进行分离和纯化，并通过 LC/MS 进行鉴定。基于水解度和抗氧化活性，用水最优提取鳄鱼肉蛋白，并通过木瓜蛋白酶进行水解。通过超滤将水解物分为 3 kDa、3-30 kDa 和≥30 kDa 三个部分。3 kDa 部分显示出水解物的最大抗氧化活性。其活性肽通过硅胶柱层析和硅胶 TLC 分离和纯化，根据活性的 TLC 生物自显影测定。通过 LC/MS 将四个高活性肽鉴定为 SSLTIQFVEGQFVDSYDPTIENTFTK、VPPHIY、VAPEEHPVLLTEAPLNPK 和 RNGLPGPIGPAG。鉴定的肽被合成，在 DPPH 和 ABTS 测定中，在 1.0 mg/mL 时的自由基清除活性达到 50%，与 0.5 mg/mL 的抗坏血酸相当或更高。结果表明，鳄鱼肉的 3 kDa 水解肽具有高抗氧化活性，并且可以通过硅胶柱层析和 TLC 有效地分离和纯化活性肽。
