Kinetics of Hypoglycemic α-Glucosidase Inhibitory Protein

• Main Author: Fahad A. Al-Dhabaan
• Format: Article
• Language: English
• Published: Journal of Pure and Applied Microbiology 2018-03-01
• Series: Journal of Pure and Applied Microbiology
• Subjects: antidiabetics; diabetes mellitus; enzyme kinetics
• Online Access: https://microbiologyjournal.org/kineticsof-hypoglycemic%ce%b1-glucosidase-inhibitory-protein/

The activity of a-glucosidase enzyme (EC 3.2.1.20) was inhibited by 40.3% by an extracellular inhibitory protein which isolated from the culture filtrate of Aspergillus brasiliensis ATCC-16404. The maximum activity of this protein and fungal mycelial dry weight were obtained at 28°C, 7 days, 6.5, 400 µl/ml, 140 rpm, and rice straw as the optimum incubation temperature, incubation period, pH value, inoculum size, agitation speed, and raw material respectively. The a-glucosidase inhibitory protein (AGIP) was purified and separated electrically as a single band at 40 KDa. There 17 amino acids of the purified protein were determined at different concentrations, where threonine has a highest percentage (90%) and aspartic acid has a lower percentage (24%). Kinetics of AGIP were determined, where Vmax, Km, kcat, and catalytic activity values were exactly calculated using Lineweaver-Burk plot compared with those of acarbose as an inhibitor standard. The maximum catalytic activity (7.808 M-1S-1) at 0.1 mg/mol was higher than that of acarbose (7.783 M-1S-1) at the same concentration.