Vitamin D3 as an Activator of Glycogen Phosphorylase b

Voiceover

Presenter(s)

Elise McCall

Abstract or Description

Glycogen phosphorylase b is the enzyme that breaks down glycogen into glucose 1-phosphate, which is then used in glycolysis or converted to glucose to maintain blood glucose level. Vitamin D is a fat-soluble vitamin used in the uptake of calcium and phosphorus. A deficiency in vitamin D can cause bone disorders and can cause fatigue. To test if Vitamin D had an effect on glycogen phosphorylase b, enzyme assays of the reverse reaction of phosphorylase were performed, yielding glycogen and inorganic phosphate, and product formation was monitored using absorbance spectrometry. In addition to studying vitamin D, a known activator, AMP, and a known inhibitor, D-glucose, were studied. Results showed increased phosphorylase activity in the presence of vitamin D and AMP, and inhibited activity in the presence of glucose. However, due to the concentration of vitamin D and its lipophilic nature, it is unlikely there was any vitamin D in solution, and the activating effects observed were most likely caused by the large amount of calcium carbonate in the supplement tested. Further testing is necessary to determine the kinematic effects of Vitamin D on glycogen phosphorylase b.

Mentor

Dr. Roberto De Guzzman