H2O2 is commonly known as hydrogen peroxide and it is a strong oxidizer and a naturally produced compound in humans as a by-product of oxidative metabolism. Because of this, humans also produce the enzyme catalase peroxidases in order to convert small amounts of H2O2 into oxygen and water. It uses the following chemical formula:
2H_2 O_2→O_2+〖2H〗_2 O
This process is called decomposition as two hydrogen peroxide molecules are broken down into oxygen and two water molecules.
Catalase is an important enzyme that protects cells from oxidative damage, which hydrogen peroxide can cause. It is an incredibly efficient enzyme where one catalase molecule can convert millions of hydrogen peroxide molecules each second.
This experiment looked at how substrate concentration can affect enzyme activity. In this case the substrate was hydrogen peroxide and the enzyme was catalase. Pieces of meat providing the catalase were added to increasing concentrations of hydrogen peroxide in order to measure the effect of hydrogen peroxide concentrations on the enzyme’s activity. The variable measured was oxygen produced, as water would be too difficult to measure with basic equipment.
What is the effect of the concentration of a hydrogen peroxide solution on catalase activity?
The hypothesis is that catalase activity will increase exponentially with higher concentrations of hydrogen peroxide until all catalase active sites are filled, in which case the activity will plateau.
Independent variable: Hydrogen peroxide concentration
Dependent variable: Oxygen production
Controlled variable(s): the surface area of the meat pieces (size and shape were controlled) which affects the concentration of catalase. The same type of meat (liver) and species (cow) was used. All pieces came from the same liver, thereby using only a single animal in the experiment. The temperature of the meat was controlled, aka kept at room temperature. All tries were measured to the same level of oxygen before stopping the timer. The same air syringe was used to measure the oxygen, and it was ensured that the hydrogen peroxide solutions covered the meat pieces during the experiment.
Equipment: Air syringe, cow liver, and 30% hydrogen peroxide
Prepare hydrogen peroxide solutions using concentrations of 30%, 15%, 7.5%, 3.75%, 1.88%, and 0.94%. Solutions should be 100mL and there should be two of each concentration.
Prepare beef liver by cutting it into similarly shaped and sized rectangles. Attempt to obtain the same relative surface area for each piece.
Set up air syringe and flask. The air syringe should be held horizontally for the experiment, to ensure gravity is not affecting the results. The distance between the flask and the syringe should be close enough that the stopper can be fully pushed into the mouth of the flask.
Begin with the 0.94% solution and work upwards. Pour the solution into the flask and ensure that the stopper is at hand....