Simple polyacrylamide affinity gel electrophoresis using oleic acid for the isolation of chymotrypsin inhibitor

Protease inhibitors have been usually isolated through a number of steps using various chromatographical methods, which are time consuming and tedious. In this report, an efficient and low-cost acrylamide affinity gel electrophoresis method for the detection and isolation of chymotrypsin inhibitor from a crude extract was studied. The affinity gel was obtained by immobilization of chymotrypsin on 5% (w/v) poly acrylamide-oleic acid gel, and the immobilized chymotrypsin showed high stability under varied concentrations of urea (0 to 8 M), pH (4 to 10) and temperature (30 to 80 °C). The affinity gel made of immobilized chymotrypsin was applied to polyacrylamide affinity gel electrophoresis and reverse electrode electro-elution using a modified commercial electrophoresis kit. Polyacrylamide affinity gel electrophoresis method showed higher isolation efficiency for chymotrypsin inhibitor from Ganoderma lucidum crude extract than a chromatographical method. Specific activity and yield of chymotrypsin inhibitor increased around 2.3-folds and 1.4-folds, respectively, compared with a chromatographical method. Also, two isomers of the inhibitor could be isolated by this method. Therefore, this method can be applied for the detection and isolation of bio-active molecules as a fast and economical method.