Essential groups and stability of α-glucosidase ofPenicillium notatum

Abstract

--Glucosidase ( -D-glucoside glucohydrolase, EC 3.2.1.20) was isolated from Penicillium notatum. The enzyme was induced by gibberellic acid (GA 3 ). The GA 3 -mediated increase in the enzyme activity was repressed in presence of abscisic acid, cycloheximide and the antibiotics chloramphenicol, cordycepin, and rifampicin which are inhibitors of protein synthesis. -Glucosidase was purified 440-fold with of 27.8-fold of purification. The enzyme was immobilized using chitosan gel. The optimal pH values were 6.5 and 7.5 for free and the immobilized enzymes, respectively. The optimal temperatures were 50 and 65 °C for free and immobilized enzymes, respectively. The enzyme hydrolyzed maltose, sucrose, isomaltose, maltotriose but not starch, amylopectin and amylose. Trehalose and glycerol protected the free and immobilized enzymes against inactivation at 70 °C, however trehalose was the better protector. Phytate protected the free enzyme against heat inactivation at both 65 and 70 °C. 2,4,6 Trinitrobenzenesulfonic acid, butanedione and diethylpyrocarbonate inactivated the enzyme and suggest that, lysyl, arginyl and histidyl groups are taking part in enzyme catalysis. The inactivation by the three compounds was protected by the substrate para-nitrophenyl--D-glucopyranoside. Treatment of the enzyme with 1-ethyl-3(3-dimethyl aminopropyl)-carbodiimide, p-chloromercuribenzoate, N-bromosuccinimide, N-acetlyimidazole revealing the involving of carboxyl, sulfhydryl, trptophenyl and tyrosyl groups, respectively in the catalysis of -glucosidase. EDTA, o-phenanthroline, dipyridyl and 8-quinolinol inhibited the enzyme activity and the inhibition was higher in case of free enzyme compared with immobilized enzyme.

Nanocapsules containing Saussurea lappa essential oil: Formulation, characterization, antidiabetic, anti-cholinesterase and anti-inflammatory potentials

“…In a subsequent study, the increased sensitivity of insulin to uptake glucose by costunolide was ascribed to the stimulation of the beta islets to secrete insulin (Li et al, 2004). Regarding the chemical structure of diabetes controlling key enzymes, almost all α-glucosidases are reported to be highly inhibited by sulfhydryl-binding reagents (El-Shora et al, 2009;Faridmoayer and Scaman, 2005). This may explain the potent inhibitory activity of SL-EO against this enzyme.…”

Nanoparticles encapsulating sesame seeds (Sesamum indicum) oil: Physicochemical, antioxidant and enzymatic inhibition properties

“…revealed also that sesame oil was more effective in inhibiting α glucosidase compared to α amylase. As mentioned previously concerning the chemical structure of diabetes key enzymes, almost all α-glucosidases are extremely inhibited by sulfhydryl groups-binding reagents[87,88]. Additionally, Su et al reported that oleic acid was a competitive inhibitor of α-glucosidase[89].…”

In vitro biological studies and computational prediction-based analyses of pyrazolo[1,5-a]pyrimidine derivatives

“…a-Glucosidase is a crucial enzyme in carbohydrate digestion, breaking down linear and branched isomaltose oligosaccharides to release glucose and causing postprandial hyperglycemia. 77 El-Shora and his team 78 visualized and conrmed the a-glucosidase using SDS-PAE, showing a single band with a molecular weight of 45 kDa.…”