Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen, 40002, Thailand.
Protein J. 2014 Feb;33(1):24-31. doi: 10.1007/s10930-013-9536-8.
Antioxidant peptides were isolated from the leukocyte extract of the Siamese crocodile, Crocodylus siamensis. Crocodile leukocyte was extracted by a combination of methods including freeze-thawing, acetic acid extraction and homogenization. The peptides in the leukocyte extract were purified by anion exchange chromatography and reversed phase-high performance liquid chromatography. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay was used to evaluate the antioxidant activity of the elution peaks at each purification step. As a result, there were two purified peptides exhibiting strong antioxidant activity in reducing free radicals on DPPH molecules. The amino acid sequences of these peptides were determined by LC-MS/MS as TDVLGLPAK (912.5 Da) and DPNAALPAGPR (1,148.6 Da), and their IC₅₀ values were 153.4 and 95.7 μM, respectively. The results of this study therefore indicate that leukocyte extract of C. siamensis contains peptides with antioxidant activity which could be used as a novel antioxidant.
抗氧化肽是从暹罗鳄白细胞提取物中分离得到的。采用冻融、醋酸提取和匀浆相结合的方法提取鳄鱼肉白细胞。采用阴离子交换层析和反相高效液相色谱法对白细胞提取物中的肽进行纯化。采用 1,1-二苯基-2-苦基肼（DPPH）自由基清除试验评价各纯化步骤洗脱峰的抗氧化活性。结果表明，有两种纯化肽在还原 DPPH 分子自由基方面表现出很强的抗氧化活性。通过 LC-MS/MS 确定这些肽的氨基酸序列为 TDVLGLPAK（912.5 Da）和 DPNAALPAGPR（1,148.6 Da），其 IC₅₀ 值分别为 153.4 和 95.7 μM。因此，本研究表明暹罗鳄白细胞提取物中含有具有抗氧化活性的肽，可作为一种新型抗氧化剂。
