The 0.1% SDS-12.5 polyacrylamide gel electrophoresis. Sample were prepared by boiling for 3 min in a sample buffer (50 mM Tris-HCl pH 6.8, 2% SDS, 0.1% bromophenol blue, 10% glycerol. M: molecular weight markers (Albumin bovine serum, 66,000; ovalbumin, 45,000; glyceraldehydes-3-phosphate dehydrogenase, 36,000; carbonic anhydrase 29,000; trypsinogen 24,000; trypsin inhibitor, 20,000; α-lactalbumin, 14,200 and Aprotenin, 6,500).