Action of Bovine and Ovine α-Amylases on Various Starches

Abstract

The actions of porcine, bovine, ovine and fungal α-amylases on five solubilized starches were investigated. The substrates used were potato, corn, rice, wheat and protozoal starch. Enzyme activities were determined by measuring maltose and limit dextrin production, glucose production, and the breakdown of the starch molecule. Large differences were noted in the action of the amylolytic enzymes from different species fed different starches. The bovine and ovine enzymes appeared to be inferior to the porcine and fungal enzymes in the breakdown of the different starch molecules. When maltose and limit dextrin production was used as the measure of activity, the bovine and ovine enzymes appeared to be superior to the porcine and fungal enzymes. Glucose production was low in all cases. Corn appeared to be poorly attacked by these amylases if the breakdown of the starch molecules was the only criterion of enzyme action. However, cornstarch was second only to potato starch as a substrate for maltose and limit dextrin production. The production of maltose and limit dextrin from cornstarch was similar for the three pancreatic amylases. The Michaelis constants and activation energies were also similar for all three pancreatic enzymes.