草鱼α2巨球蛋白的分离纯化与若干特性

摘要

α2-Macroglobulin was purified from grass carp plasma by precipitation with polyethylene glycol (PEG) 6000,gel filtration and anion-exchange chromatography. The three steps of the procedure resulted in the purification of grass carp plasma α2 M. The purified product was analyzed by polyacrylamide gel electrophoresis (PAGE) under natural conditions and the proteins showed a single band. Meanwhile, it was analyzed by SDS, PAGE under reducing conditions and the proteins showed double bands with molecular weight of about 95 kD and 80 kD. This result demonstrated that grass carp α2M was composed of two distinct subunits. Most properties of grass carp α2M were similar to that of human α2M. Grass carp α2M treated with trypsin produced the fast form of the molecule more mobile in PAGE, but the untreated grass carpR2M had the property of electrophoretically slow-form. α2M was a nonspecific proteinase inhibitors of blood plasma. Inhibition of activity of Aeromonase hydrophilas extracellular proteinase (AhECPase) showed that grass carp α2M could inhibit the proteinases secreted from invading bacteria. Double immudiffusion of α2M demonstrated no cross-antigenicity between grass carp' s and human α2M