Smart2pure3 barnstead aqua purification system

α-Amylase from human saliva (A0521-500 UN; Type IX-A, lyophilized powder 1000–3000 U/mg protein), porcine pepsin from gastric mucosa (P6887-1G, lyophilized powder 3200–4500 U/mg protein), pancreatin (P7545, lyophilized powder, 8 X USP), and porcine bile extract (B8631, lyophilized powder) were purchased from Sigma–Aldrich (Saint-Louis, MO, USA). AEBSF- 4-(2-aminoethyl) benzene sulfonyl fluoride hydrochloride was purchased from Fluka, Ref: 76307 (Sigma-Aldrich, Saint-Louis, MO, USA). All other chemicals were of analytical reagent grade and purchased from Sigma–Aldrich (Saint-Louis, MO, USA), unless stated otherwise. In all experiments, ultra-pure deionized water (18 mΩ) was used (Smart2Pure3™ Barnstead aqua purification system (Thermo Fisher Scientific, Waltham, MA, USA)). The enzyme activities were measured according to the assays detailed by Brodkorb and colleagues [10 (link)]. A mixture of seven native proteins (14.4–116 kDa), unstained for use as size standards in protein electrophoresis, were purchased from Thermo Fisher Scientific (Waltham, MA, USA).