Enzymes accelerate biological reactions and their reaction rates depend on conditions like temperature and pH levels. The workshop explored how altering conditions affected catalysis and reaction rates using the enzyme p-nitrophenyl glucopyranoside. Experiments showed this enzyme works best at pH 5, where it hydrolyzes starch into glucose and p-nitrophenol, detected by its yellow color. Samples tested at different pH levels found only pH 5 turned yellow, and spectrometer readings confirmed more products formed at lower pH, demonstrating pH significantly impacts the enzyme's reaction rate.

1. Workshop: Biofuels
By Ricardo Chiesa
Enzymes are proteins that are involved in biological reactions and their main
function is to accelerate these processes. The reaction rate consists on how fast or slow a
reaction takes place. The purpose of this workshop was to work with an enzyme and to
alter normal conditions to see how catalysis is affected, and also to see reaction rates. The
biological functions of enzymes are affected by temperature and pH levels, and the reaction
rates are affected by the concentration of substrates and enzymes. The enzyme that I
worked with was the p-nitrophenyl glucopyranoside, an analogous of the cellobiose, an
enzyme involved in the breakdown of starch into two glucose molecules. The analogous
enzyme, along with water, hydrolyses the starch and breaks it down into a molecule of glucose and
p-nitrophenol. This last molecule reflects a yellow color in solution, and thus is very useful for
determining whether a reaction occurs or not. My lab partner and I worked determining the effect
of pH on the reaction rate. We tested it in different pH level solutions (pH 5, pH 6.3, and pH 8.6).
It was observed that the pH 5 solution was the only one that turned yellow. This means that pH 5 is
the optimum level for more catalysis to occur. Then, these samples were put into a spectrometer to
measure the absorbance of each sample. At the end, using a calibration curve with the relationship
of the absorbance numbers and quantity of products, it was determined that more products are
visible as pH level decreases.