Salivary Amylase

Wheat, potatoes, corn and rice contain starch and starch is a major component of the modern diet. Amylase enzymes secreted in saliva help break down starches into simple sugar molecules that can be absorbed into the bloodstream, influencing blood glucose levels.
Monell Center scientists have undertaken a study which revealed that changes of starch consistency in the mouth were directly related to salivary amylase activity. In this study:

• saliva was collected from 73 subjects
• saliva was mixed with a standardized starch solution, and a sensor measured the enzymatic break-down of the starch's consistency
• enzyme and protein assays directly measured the amount and activity of salivary amylase in the saliva samples
• subjects completed a survey to rate the perceived breakdown of a starch sample in the mouth over a minute

Foods with different starch levels were perceived differently by people depending on how much salivary amylase they produce. "What may seem like a thick and resistant pudding or starchy food to some may seem noticeably thin in the mouths of others", said Monell sensory geneticist Paul A. S. Breslin.
Individuals who have more salivary amylase may break down starchy foods more quickly, leading to more rapid increase of post-meal blood glucose levels. It is possible that high levels of salivary amylase contribute to the risk of insulin resistance and non-insulin dependent diabetes.

Reference:
Abigail L Mandel, Catherine Peyrot des Gachons, Kimberly L Plank, Suzanne Alarcon, Paul A S Breslin. Individual Differences in AMY1 Gene Copy Number, Salivary α-Amylase Levels, and the Perception of Oral Starch. PLoS ONE, 2010; DOI: 10.1371/journal.pone.0013352

Further Reading
http://www.ausetute.com.au/enzymes.html
http://www.ausetute.com.au/sugars.html

Study Questions

1. Give a general chemical formula for starch.
2. Starch is an example of a biological polymer. Of what monomers is this polymer made up of?
3. Another biological polymer is made up of the same monomers as that of starch, but, it is found in animals instead of plants. What is the name of this polymer?
4. Assuming you were given two sample bottles, one contained the plant polymer starch, and the other contained the animal polymer in question 3. What simple test or tests could you perform to identify which bottle contained the plant polymer and which contained the animal polymer?
5. What is meant by the term enzyme?
6. Draw a diagram to represent how amylase acts on starch to produce simple sugars.
7. Assume one of the subjects in the study had a fever and was found to have a temperature of 40^oC. What effect would this have on the results obtained during the survey phase of the study?
8. Imagine a well-wisher gave our sick subject above a "nice, hot lemon drink" to relieve the fever's symptons just before the saliva sample was collected. What impact would the lemon drink most likely have on the level of amylase activity?