Determining the activity of glycogen phosphorylase b with various effectors

Voiceover

Presenter(s)

Nathan Do

Abstract or Description

Oxidation of glucose plays a significant role in energy production for nearly all living organisms. While excess glucose is stored as glycogen, glycogen phosphorylase b (GPb) catalyzes the extraction of glucose 1-phosphate from glycogen for immediate energy use. However, the rate at which GPb enzymatically cleaves glycogen is often impacted by numerous effectors that either inhibit or activate the enzyme. With commercial products consistently being produced, advertising effects of immediate energy, further studies are needed to understand how such conglomeration of chemicals impact GPb. I am interested in exploring the impacts of 5-hour ENERGY® by conducting enzyme kinetic assays with GPb and various concentrations of the 5-hour ENERGY® effector. Assays were conducted by creating a reaction mixture of glucose 1-phosphate and glycogen along with any tested effectors (adenosine monophosphate, (±)-epinephrine hydrochloride, and 5-hour ENERGY®). As glucose 1-phosphate is added to glycogen, a free inorganic phosphate is released, interacting with molybdate ions. The absorbance of the reaction mixtures was collected to determine the enzyme activity. The assays tested exhibit adenosine monophosphate as an activating effector for GPb while (±)-epinephrine hydrochloride and 5-hour ENERGY® as an inhibiting effector. This suggests that effectors that signify low energy (AMP) may activate GPb for cleavage of glycogen; while effectors that enhance energy inhibit such activity. Ultimately, this study attempts to understand the implications of how GPb interacts with effectors, which may provide additional knowledge in human metabolism.

Mentor

Roberto De Guzman