Carbohydrases in camel (Camelus dromedarius) pancreas. Purification and characterization of glucoamylase.
The present study analyzed the existence of carbohydrases in camel pancreas compared to some other ruminants. Disaccharidases (maltase, cellobiase, lactase, trehalase and sucrase), glucoamylase and alpha-amylase were detected in pancreas of camel, sheep, cow and buffalo. Enzyme levels in sheep were lower than in the other ruminants. The highest level was detected for alpha-amylase (EC 3.2.1.2). Moderate activity levels were detected for glucoamylase (EC 3.2.1.3) and maltase (EC 3.2.1.20), while other disaccharidases showed very low activity. The results suggested that, in addition to alpha-amylase, glucoamylase and maltase may be synthesized and secreted from pancreas to the small intestine in ruminants. Camel pancreatic glucoamylase was purified and characterized. The purification procedure included glycogen precipitation and chromatography on DEAE-Sepharose and Sepharose 6B. The molecular mass was 58 kDa for native and denatured enzyme using gel filtration and SDS-PAGE, respectively. The enzyme had a pH optimum at 5.5 and a Km of 10 mg starch/mL with more affinity toward potato soluble starch than the other carbohydrates. Glucoamylase had a temperature optimum at 50 degrees C with heat stability up to 30 degrees C. The effect of different cations and inhibitors was examined. The camel pancreatic glucoamylase may possess an essential thiol.
Mohamed
Saleh A
SA
Molecular Biology Department, National Research Centre, Cairo, Egypt. saleh38@hotmail.com
Fahmy
Afaf S
AS
Mohamed
Tarek M
TM
D000818:Animals; D002162:Camelus; D002412:Cations / Q000494:pharmacology; D002417:Cattle; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005087:Glucan 1,4-alpha-Glucosidase / Q000302:isolation & purification* / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007421:Intestine, Small / Q000201:enzymology; D008970:Molecular Weight; D010179:Pancreas / Q000187:drug effects / Q000201:enzymology*; D012756:Sheep; D000516:alpha-Amylases / Q000302:isolation & purification / Q000378:metabolism*; D000520:alpha-Glucosidases / Q000302:isolation & purification / Q000378:metabolism*
D002412:Cations; D004791:Enzyme Inhibitors; D000516:alpha-Amylases; D000520:alpha-Glucosidases; D005087:Glucan 1,4-alpha-Glucosidase