Abstract: In order to discuss the preparation and antioxidant activity of enzymatic hydrolysis peptide of north Pacific squid gland,peptide was extracted from the north Pacific squid gland by Alkaline protease,the hydrolysis degree and1,1 diphenyl-2-picrylhydrazyl（DPPH） free radical clearance rate were the index,studied through single factor and orthogonal experiment to obtain optimum enzymolysis conditions. Ultrafiltration get different molecular peptides,different molecular weight peptide oxidation resistance was evaluated by testing the scavenging activity of hydroxyl reducing power, DPPH clearance,Fe²⁺ chelating ability,OH free radicals and superoxygen anion,it was concluded that the best molecular peptide. Using Agarose gel G-25 separate the best molecular peptide and detect the DPPH scavenging ability of each peak,then the best peak was further isolated to a single component by HPLC, the amino acid sequencer degrade n-terminal and get the target peptide sequence. Degree of hydrolysis reached to maximum under the conditions of enzymolysis temperature 50 ℃,enzymolysis time 7 h,total enzyme dose 3 500 U/g,solid-liquid ratio 1∶6 and pH 9. The strongest antioxidant activity was 3-5 ku molecular period through ultrafiltration,three peak was isolated by Agarose gel G-25,and the components of peak Ⅰ had the best DPPH scavenging ability,and with the concentration of 0.5 mg/mL of DPPH the scavenging ability was 61.87%. Then a single piece was further isolated by HPLC,and the amino acid sequence is Ala-Tyr-Ala-Ser-Ser,relative molecular mass is 497.50. So the north Pacific squid gland has a good antioxidant activity.

Key words: Todarodes pacificus, squid nidamental gland, antioxidant, oligopeptides, HPLC, G-25