Purification and characterization of α2-macroglobulin from chum salmon plasma

Chum salmon plasma α₂-macroglobulin (α₂-M) was first purified by polyethylene glycol gradient precipitation, gel filtration and anion-exchange chromatography from chum salmon plasma. The α₂-M was purified 47.77-fold with a yield of 28.90% towards papain. The α₂-M showed molecular weight (Mw) of 175 kDa and consists of two different subunits of Mw 95 kDa and 80 kDa, respectively. The α₂-M was stable towards papain and trypsin at pH ranges from 5.0 to 8.0, and was thermal stable at temperatures below 50°C. The α₂-M was applied to Alaska pollock surimi and was able to inhibit the gel weakening in a concentration-dependent manner.