Title of the Project: Influence of Lumanutrition Berberine Tablets on Glycogen Phosphorylase 

Voiceover

Presenter(s)

Kai Smith

Abstract or Description

One of the key enzymes in glycogenolysis is glycogen phosphorylase, which catalyzes the release of glucose-1-phosphate, supplying glucose for metabolic processes such as glycolysis. Given its central role, glycogen phosphorylase is a common target for regulation via activation or inhibition.

This study aims to determine whether the molecule berberine, a quaternary ammonium salt from the protoberberine group of benzylisoquinoline alkaloids, functions as an activator for glycogen phosphorylase. Lumnutrition sells it as a dietary supplement and claims it increases energy levels by promoting glycogen breakdown. Kinetic assays were performed using increasing concentrations of inactive glycogen phosphorylase B in varying concentrations of the activator AMP and Berberine at high to low concentrations (10-2.5 g/mL). Inorganic phosphate served to measure reaction progress, quantified via spectral absorbance at 600 nm.

Results showed that in 4 mM AMP, berberine exhibited a Vmax which increased by 9.7%, while Km decreased by 81.3% when the concentration of berberine was decreased. In 0.5 mM AMP, Vmax and Km both increased by 12.6% and 71.9%, when the concentration of berberine was lowered. These findings suggest that berberine acts as a competitive inhibitor of glycogen phosphorylase B or a mixed inhibitor, given the increasing Vmax and Km trends. The large initial Km decrease observed is likely due to experimental errors during the high-concentration assay with 4 mM AMP, thus requiring further kinetics assays to confirm the activity of berberine.

Mentor

Roberto De Guzman