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Cloning, expression, and characterization of a porcine pancreatic α-amylase in Pichia pastoris

Animal Nutrition • 2018
العودة
معلومات البحث
المؤلفون Lv-Hui Sun, Tao Qin, Yan Liu, Hua Zhao, Xin-Jie Xia, Xin Gen Lei
الكلمات المفتاحية Not Available
المجلة العلمية Animal Nutrition
الناشر Not Available
المجلد Not Available
العدد Not Available
الصفحات Not Available
publication.type International
رابط البحث Open Link
المواد المرفقة Not Available
الملخص
Pancreatic α-amylase (α-1, 4-glucan-4-glucanohydrolase, EC.3.2.1.1) plays a primary role in the intestinal digestion of feed starch and is often deficient in weanling pigs. The objective of this study was to clone, express, and characterize porcine pancreatic α-amylase (PPA). The full-length cDNA encoding the PPA was isolated from pig pancreas by RT-PCR and cloned into the pPICZαA vector. After the resultant pPICZαΑ-PPA plasmid was transferred into Pichia pastoris, Ni Sepharose affinity column was used to purify the over-expressed extracellular recombinant PPA protein (rePPA) that contains a His-tag to the C terminus and was characterized against the natural enzyme (α-amylase from porcine pancreas). The rePPA exhibited a molecular mass of approximately 58 kDa and showed optimal temperature (50 °C), optimal pH (7.5), Km (47.8 mg/mL), and Vmax (2,783 U/mg) similar to those of the natural enzyme. The recombinant enzyme was stable at 40 °C but lost 60% to 90% (P < 0.05) after exposure to heating at ≥50 °C for 30 min. The enzyme activity was little affected by Cu2+ or Fe3+, but might be inhibited (40% to 50%) by Zn2+ at concentrations in pig digesta. However, Ca2+ exhibited a dose-dependent stimulation of the enzyme activity. In conclusion, the present study successfully cloned the porcine pancreatic α-amylase gene and over-expressed the gene in P.pastoris as an extracellular, functional enzyme. The biochemical characterization of the over-produced enzyme depicts its potential and future improvement as an animal feed additive.