One factor contributing to the prevention of diabetes mellitus and its complications is the control of postprandial blood glucose levels by the consumption of an appropriate diet. Our proposed delivery mechanism of the 0.19 wheat albumin is through miso, a staple Japanese bean paste. The albumin is an α-amylase inhibitor, which hinders the ability of α-amylase to hydrolyze starch into absorbable glucose monomers. Specific amino acid substitutions were made in 0.19 to improve inhibitory activity. The 0.19 wheat albumin is an odorless, colorless, heat-resistant protein with minimal flavour, shown to reduce glucose spikes. In addition to this, it has already been approved for use in blood-glucose-level-suppression in Food for Special Health Uses, which makes it a good candidate for a dietary supplement.
During our visit to the Mitaka Diabetes Clinic in Mitaka, Tokyo, we learned that a supplement reducing amylase activity could theoretically lessen dietary restrictions for pre-diagnosed and diabetics by preventing the breakdown of starch chains in foods of the traditionally high-carb Japanese diet. Therefore, we concluded that 0.19 wheat albumin to better reduce amylase activity could serve as a potential supplement that would allow consumers to continue to enjoy the traditional Japanese diet.
If used as a food supplement, 0.19 would theoretically be secreted into the miso delivery mechanism; therefore, we simulated these conditions by having our yeast actively secrete 0.19 Wheat Albumin into the surrounding solution, mimicking the action of the proposed modified yeast in the miso supplement that would perform this function. When tested in vitro, we successfully demonstrated that α-amylase was inhibited by 0.19 secreted in solution and inhibit α-amylase activity as can be seen in the figure below. This demonstrated that if this yeast were actually placed in miso, it would be able to produce 0.19 albumin.
Finally, we aimed to improve the binding affinity of 0.19 wheat albumin to α-amylase. By strengthening the bonds between 0.19 and α-amylase the inhibitory activity would be extended and further prevent the breakdown of starch as it travels through the digestive tract. Although we did not test this in vivo, our amino acid modifications showed a significant decrease in amylase activity overall, indicating that the glucose spike would be suppressed even further.
The most successful modification made to 0.19 were the Glycine to Glutamic Acid (N), the fourth amino acid in the chain, and Isoleucine to Asparagine (E), the forty-fourth amino acid the chain. Since there is a significant decrease in amylase activity in our modified 0.19, compared to unmodified 0.19, we concluded that we successfully were able to extend the inhibitor activity of 0.19 wheat albumin.
