Structural characterization and bioactive screening of two homogeneity proteins from Tianshan red deer abomasum

In this study, response surface methodology (RSM) and Box-Behnken design (BBD) were used to optimize the process of extracting abomasum protein from Tianshan red deer. The final extraction conditions were as follows: ultrasonic power: 445 W, extraction temperature: 43 °C, and extraction solution salt concentration: 0.57 mol/L. Gel chromatography and anion exchange chromatography were applied to isolate two homogeneity proteins named A1 and A2 from the abomasum of Tianshan red deer. The protein contents of A1 and A2 were 71.57% ± 5.65 and 68.83%±4.35 respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) determined the molecular weights of two homogeneity proteins to be 63 kDa and 55 kDa. The secondary structures of two homogeneity proteins are primarilyβ-folds and α-helixes. In addition, activity screening revealed the anti-inflammatory property of A1 (78.67% ± 2.23 inhibition of cyclooxygenase 2 (COX-2) at 0.1 mg/ml) and the anti-tumor activity of A2 (79.38% ± 3.52 and 85.89% ± 3.37 inhibition of human colon cancer cells (HCT-116) and human gastric cancer cells (HGC-27), respectively, at 1 mg/ml). These findings suggest that protein from the abomasum of Tianshan red deer may be useful as an efficacy factor in foods and nutraceuticals.