Trypsin inhibitor is a competitive serine protease inhibitor that inhibits trypsin, chymotrypsin, kallikrein and plasmin. Trypsin inhibitor forms stable complexes with and blocks the active sites of enzymes. Binding is reversible with most trypsin inhibitor-protease complexes and dissociating at pH <3.0. Effective concentration is equimolar with protease. SAB recombinant trypsin inhibitor is a genetically engineered protein expressed in E.coli and purified by multi-column.The amino acid sequence of recombinant trypsin is identical to bovine lung derived trypsin inhibitor,with equivalent properties compared to native trypsin inhibitor and can replace native trypsin for using in a variety of biotechnological processes.