Enzymes are organic proteins that help chemical reactions occur in all living organisms and are found all over nature. Enzymes are catalysts that help accelerate reactions, remarkably they are not changed in reactions, instead the substrates are converted into products when they bid to the enzyme active site. All enzymes have a specific function, this means that they are specialized for a certain substrate and will only ever react with that substrate.
All enzymes have specific structures, this allows them to carry out so many different tasks. They are considered the most structurally sophisticated molecules known, inevitably their structure and function vary immensely (Urry et al. ,2016). Each protein has an exclusive three-dimensional shape. Enzymes are made up of amino acids that are linked together by peptide bonds in a line, this resulting chain in called a polypeptide (protein); this is and enzymes primary structure. All amino acids have an amino group (NH2) and a carboxyl group (COOH) at each end bonded to a central carbon atom (alpha carbon) that has a hydrogen atom and a side chain (R Group) bonded to the opposite ends. This protein chain folds up on itself in two ways, one is by wrapping around forming a helix or by folding on top of itself forming a sheet, this is called secondary structure. It can do this because the hydrogen from the amino group and the oxygen in the carboxyl group bond with each other by forming hydrogen bonds, this allows amino acids in the same chain can interact with each other. Then there is tertiary structure, the overall shape of polypeptides developing from interactions between side chains (R Groups) of multiple amino acids. Finally, there is the Quaternary structure, this structure is just combining of multiple polypeptide sub units, picture multiple tertiary structures forming together like a blob.
Enzymes can be affected by a handful of factors like temperature, ph., enzyme concentration, substrate concentration and the presence of any inhibitors or activators. Some enzyme catalyzes the oxidation of organic substrates by transferring hydrogen and electrons from a substrate to hydrogen peroxide. One of the examples of this chemical reaction are, Microbodies in animals, plants and fungal cells. Microbodies are believed to help detoxify cellular waste products one of which is hydrogen peroxide that is produced as a toxic by product in cell aerobic respiration (Symbiosis Manual, 2011).
We also know that molecules exposed to different temperature react differently ether by cooling or heating them. To make something warmer we add heat energy, this makes molecules of hydrogen and oxygen vibrate and move faster. If we cool water the molecules slow down and move slower, this proposes that enzyme molecules might behave in similar ways. If substrates and heat already influence how molecules and enzymes behave then the addition of more heat and a higher concentration of enzymes can help speed up chemical reaction and the rate at which they do it. Just as humans have a set body temperature to carry out all body functions optimally. Enzymes must have a prefer temperature where they could reach the highest rate of reaction, too hot and they could denature, too cold and the reaction could stall.
The Enzyme Peroxidase and a substrate called guaiacol were used to test the effect or higher enzyme concentration. Peroxidase is one of the enzymes that catalyze the oxidization of organic compounds by hydrogen peroxide through the organic the compound guaiacol (substrate). An enzyme extract was prepared with horse radish and a buffer with a ph. of 7.0 blended and strained mixture. Then eight test tubes were prepared with various dilutions of relative enzyme concentration all in pair 2-3,4-5 etc. They were obtained by following a chart on the lab manual and adding various volumes of the enzyme extract mixed with buffer with ph. 5 and guaiacol mixed with H2O2. A ninth text tube was filled with the mixture of buffer (ph. 5), H2O2, and guaiacol, this test tube was the “blank” that was used for calibration. It is important to note that there are many different enzymes present in the extract that was prepared but only the peroxidase oxidizes when the other substrate is added.
To obtain the rate of reaction, absorbance was measured, this was done by using a spectrophotometer for Precision. This machine measured the intensity of light that is refracted, absorbed or transmitted by the sample inserted in it. Using the blank test tube serves as a control for the photometer to read all samples being contrasted. This is because all solutions where colorless until the enzyme was mixed with the substrate, the blank being the only test rube with no catalyst does not go through any reaction. Therefore, the solution in the blank test tube stays colorless and served as a baseline each time a dilution set was put into the machine to recorded. Once mixed, the test tube pairs were inserted into the machine and absorbance readings were recorder every 20 seconds for two minutes. The date on the effects of enzyme concentration where the charted.
The graph data revealed that the lowest enzyme dilution concentration (0.1) had a lower rate of reaction. As the enzyme concentration becomes higher, the rate of reaction gets higher and the reagents in the reaction reach oxidization faster. The 1.0 dilution reagents reached oxidization faster but then flatlined, this means the molecules in an enzyme reaction become saturated with substrate and causes the reaction to plateaus. This plateau occurs because the enzyme is saturated, meaning that all enzyme molecules available are already being used up processing substrates this means that the rate of reaction (amount of product produced per unit time) is limited by the concentration of enzyme, this is seen in the effects of enzyme concentration on rate of reaction graph, the highest concentration is not the one with the highest rate of reaction.
We already know how temperature affects molecules, temperature would affect all four different dilution in a similar way, rather than using all dilutions in the new experiment only the dilution with the best linear results was used, dilution 0.25. For this experiment four optimal temperature were chosen, near freezing point (5ºC), room temperature(25ºC), near body temperature(34ºC) and near boiling point (60ºC). To figure out how the rate of reaction was affected part of the first experiment was repeated, eight test tube prepared in pain with enzyme extract mixed with buffer with ph. 5 and guaiacol mixed with H2O2 except only the one with the for 0.25 dilution was in the pairs. Then each set was put into incubators with their selected temperatures and left in there for an average of 10-15 minutes to reach the desired them, with exception of the room temperature pair. Data for the room temperature pair were collected first using the spectrophotometer in the same way we did for the first experiment, then the same was quickly done for the test tube pairs in the incubators one by one so that the desired temperature was maintained.
As the data was collected it was noted that the in coolest and hottest enzyme mixtures absorbance took place slower than in the room temp and body temp mixture. Enzymes at body temperature seemed to thrive because absorbance was the highest, but we can see that if temperature gets too high(60ºC) or too low (5ºC) enzymatic reaction starts to slow down and can start to denature. When we look at how temperature affects rate of reaction, we see that temperature that are too hot or too clod affect rate is affected in a similar was, enzymatic reaction is slowed. On the other hand, temperatures that are maintained between room temperature and body temperature are ideal for enzymatic reactions.