CHEM 463:Experimental Biochemistry I. Experiment 13+14:Enzyme Kinetics

Lab Report
Experiment 13+14: Enzyme Kinetics
Yalda Rawan, ArashBaghi
CHEM 463: Experimental Biochemistry I
Dr. Aschrafi
University of the District of Columbia
9/26/2018
Theory/Introduction
All living organisms need enzymes to perform their day-to-day activities, such as eating, sleeping, working and others. Enzymes are the catalytic proteins that primarily speed up chemical reactions in the body without being used themselves (2011). Some of the enzymes, however, cannot speed up any chemical reaction; instead, they alter the process slightly and play their vital role in producing a lot of energy. The molecules upon which enzymes act are known as substrates, and the molecules that are produced during a chemical reaction are known as products (2005). It should be noticed that enzymes are very picky about the conditions at which they perform their functions. For instance, if the temperature is not suitable, they may not be able to do their jobs. The same is the situation of pH, which has to be ideal for enzymes to speed up chemical reactions without any major issues. During a reaction, if the temperature is increased tremendously, the movement of molecules will get disturbed, and this will lead to numerous collisions. It will also increase the average kinetic energy of molecules in order to enable them to react properly. In simple words, we can say that enzymes can work at an optimal temperature and optimal pH only.
The core objective of this laboratory experiment was to determine how the rate of enzyme activity changes because of varying environmental factors and how much time is needed to a chemical reaction to take place. My hypothesis for this lab experiment was that when the concentration of catalase increases, the rate of reaction will also increase. This is because the substrates will not be able to change the rate of reaction. I predicted that the catalase processes hundreds of substrate molecules every second and that the rate of reaction keeps increasing.
Apparatus Set up and Chemicals Used
Table: Apparatus and Chemicals of the Lab Session
1.5 mM substrate

Four DPTPs

Beaker

Enzyme

Two 15 ml conical tubes

Colorimetric standard (S1–S5) in cuvettes

1x stop solution

One Buffer

distilled or de-ionized water to rinse DPTPs

One stopwatch

One Spectrophotometer (optional)


Method/Procedure
1 The 15 ml conical tubes labeled “Stop Solution,” “1.5 mM Substrate,”
2 “Enzyme” and “Buffer” were located and labeled in the first step.
3 Then I labeled five cuvettes E1–E5 (for five-time points) on their upper side.
4 The two remaining cuvettes were labeled as “Start” and “End” on their upper part.
5 All of the cuvettes served as control time points in the beginning and end of the reaction.
1 None of them contained the enzyme.
6 With the help of a clean DPTP, we poured 500 µl of stop solu...