3-Amino-5-Nitrosalic Acid On The Reaction Rate Of Starch

We found that, in acidic pH environment, the reaction rate of starch being broken down by alpha amylase is less than that of the reaction rate at a neutral and slightly basic pH environment. This finding partially supports our hypothesis.
The spectrophotometer readings in our experiment measured the absorbance of 3-amino-5-nitrosalicylic acid, a colored molecule formed after dinitrosalicylic acid (DNSA) has reacted with the products of the enzymatic reaction or the simple sugars. Therefore, the absorbance readings correspond to the concentration of the simple sugars produced by the reaction. In the end, the concentration of simple sugars indicated the reaction rate, as time was controlled to four minutes.
Enzymes function optimally at a specific range of pH, and most function at an optimal pH of around neutral, or 7. The results of this experiment indicate that the optimal pH may be around 7 to 8, not 7, as the reaction rate was the same at 7.2 and 7.9, and enzyme activity was decreased at pHs below 7.2.
Amino acids are the basic building blocks of proteins, such as enzymes like alpha amylase.
Though the backbones of most of the amino acids are the same, there are four different R groups that an amino acid can be classified as: nonpolar, uncharged polar covalent, negatively charged polar covalent, and positively charged polar covalent groups. The R groups of the amino acids dictate protein folding. Based on the classification of each amino acid R group, four different types interactions with the R groups of other amino acids occur, hydrogen bonds, disulfide linkages, ionic interactions, and nonpolar associations to create the tertiary structure or three-dimensional conformation, which dictates the function of a
protein.
The basic principle of form determining function can be employed here. As there is a change in the bonding or folding at any level of a protein, the function is also affected. When polar and charged amino acids, are placed in an aqueous environment with higher concentrations of charged molecules, such as H+ and OH-, the partial or full charges of the amino acid side groups tend to interact with the ions rather than the existing bonds. The charged ions, present in higher concentrations in more acidic and basic solutions, can dismantle the existing bonds as the atoms in the amino acids can now also interact with the ions. These interactions unhook the bonds holding the protein together, and lead to a change in the structure. Therefore, they alter and denature the three dimensional conformation of the protein and affect its function. By affecting the function of the enzymes, the reaction rate is affected, and lowered as witnessed in the experiment.