Abstract: In this study,combined proteolyzation of Porphyra yezoensis by 1398 neutral protease,alkaline protease and aminopeptidase was optimized using the α-glucosidase inhibitor activity as index.The α-glucosidase inhibitor from hydrolysate was initially extracted by adding 60% ethanol to precipitate and remove polysaccharides.The supernatant was further purified through SP Sepharose High Performance cation-exchange chromatography,Sephadex G-10 gel filtration chromatography and Mono Q anion exchange chromatography.The purity of the obtained peptide-type α-glucosidase inhibitor (LGI) was up to 62.4%,according to the result of reverse-phase high performance liquid chromatography (RP-HPLC).The basic characteristics of LGI indicated that it had high thermo stability and pH stability.The IC₅₀ value of LGI was 97.36 μg/mL against α-glucosidase,and it belonged to non-competitive inhibitors.

Key words: Porphyra yezoensis, protease hydrolysis, &alpha, -glucosidase inhibitor, purification, basic characteristics