Conditions that Influence the Activity of Amylase and Pancreatic Nucleases Presented by Tyler Boswell, Leah Friedman, Jacob Mingolla, Marissa Pioso Curran Bio H Tan October 20th, 2010

Hypotheses: Increasing the amylase concentration of a solution in a test tube will increase the rate of starch disappearance. Amylase will be most efficient in a pH range that is within the pH range of humans.

This graph shows the relationship between the concentration of an Amylase solution in a test tube and the rate at which the starch in that test tube is broken down by the amylase.

This graph shows the relationship between the pH of an amylase solution in a test tube and the rate at which the starch in that test tube is broken down by the amylase.

Discussion: Concentration Results support hypothesis As seen on the graph, as the concentration of amylase increases, the rate of starch reaction increases o Therefore, the amount of time for the starch to disappear decreases o Amylase is more effective in higher concentrations  There are two types of amylase: alpha amylase and beta amylase1  Alpha amylase alone is able to break down starch into complex sugars  Beta amylase attacks these sugar chains and further breaks them down into simpler sugars, limiting the alpha's job  When alpha and beta amylase are both present, starch breakdown occurs more rapidly  The higher the concentrations of both alpha and beta amylases,the more starch chains can be broken down at once, the quicker the rate of reaction

Discussion: pH Results support hypothesis As seen on the graph, Amylase is most efficient between the pH values of 6 and 7 o Thus, amylase best functions in neutral or close to neutral environments o The optimal pH value for amylase function falls within the average human parameters  Amylase is present in saliva  Bicarbonate ions, as buffers, keep salivary pH between 6.5 and  Saliva is the optimal environment for amylase activity, because the bicarbonate ions keep the pH between the levels that best promote amylase function.

Discussion: Temperature Temperature has an effect on amylase's speed of starch breakdown.3 o Amylase is most efficient at temperatures closest to human body temperature ranges.  The average human body temperature is 98.6 degrees Fahrenheit, or 37 degrees Celsius.

Discussion: Sources of Error Instructions in each lab were to immediately remove one drop of the starch and amylase mixture, as soon as it was mixed, and add it to the iodine test plate to count as "time zero". o It is possible the drop was not removed quickly enough, causing the amylase to react slightly before reaching the first iodine test, and yielding inaccurate results. o The amounts of iodine in each section of the test plate were not exactly equal. In the pH lab, specifically: o Since the class ran out of time, each group was not able to test every pH level, and shared results instead. Thus the class average time of starch disappearance would be inaccurate from a lack of data abundance, and outliers could strongly influence the averages.

Pancreatic Nucleases4 Used to break down nucleic acids o Its substrates are DNA and RNA o The resulting products are nucleotides o Dismantles nucleic acids in digesting food Created by exocrine cells in pancreas One of the four major digestive enzymes from pancreas o Secreted by the pancreas into the small intestine o Activity occurs in the small intestine Works best in neutral or slightly alkaline pH values o Contains bicarbonate (HCO3) to neutralize stomach acid

References: 1. Ramsey, Kevin. "Re: HOW & WHY DO DIFFERENT CONCENTRATION OF THE ENZYME AMYLASE EFFECT THE DIGE." MadSciNet: The 24-hour Exploding Laboratory. 6 Feb Web. 18 Oct Gregory, Michael J. "Digestive System." Clinton Community College. Web. 18 Oct "The Effect of Temperature on Amylase Activity, Page 2 of 4." Associated Content - Associatedcontent.com. 25 Sept Web. 19 Oct Starr, Cecie, and Beverly McMillan. "Digestion and Nutrition." Human Biology. 8th ed. Cengage Learning, Print.