Ryan JahansoozLab Partners: Zac Foster, Tyler VossSection 16Lab Report 2: Analysis of Protein Size and Subunit Composition Using SDS-Polyacrylamide GelElectrophoresisIntroduction: This lab covered proteins. Proteins are made of polypeptide chains. There are many types of proteins, and some are made of multiple types of polypeptide chains. These different proteins have many names such as dimers, tetramers, pentamers, or hexamers, depending on how many chains of polypeptide they are made of. Some are made of multiple of the same chain and are called homodimers, while others are mixed and are called heterodimers.There are many methods for finding the size of proteins. Two different ways, SDS-Polyacrylamide gel electrophoresis and gel filtration yield different but complementary information. The lab used SDS-PAGE to find the size of the marker protein in units called “Daltons”.SDS-PAGE works using electrophoresis to separate charged molecules, like proteins, in anelectric field. The weight is found by comparing the migration of a protein once it is fully denatured by an electric current to its folded status. Materials and Methods: This lab required the use of a special device known as a mini PROTEAN gel rig hooked up to a power source as well as a dry bath, 20µl pipettes, ice, and the samples themselves. The firststep was to clearly label each sample before placing them in the dry bath for five minutes to heat them up to 65 degrees Celsius. Once heated, the samples were carefully pipetted into individual wells in the mini PROTEAN gel rig. A current of 110V was run through the rig for one hour, which allowed the proteins to unfold enough to be accurately measured. Once denatured,a picture of the gel rig was taken under UV light and the lab was cleaned. Everything was done to according to the directions and protocol was not broken.Results:The lab exercise began with prepping the proteins for use in the mini PROTEAN gel rig bymoving them to the 65 degree Celsius dry bath for exactly five minutes. This fully denatured the proteins. Once prepared, 10 µl of each sample was placed into a separate well filled with polyacrylamide gel. After running 110V through the gel for one hour, a photo of the gel was taken by the TA and the data collection section of the lab began.Here is the picture of the gels after the experiment:Here is the graph created from the data collected:8 10 12 14 16 18 20 22050000100000150000200000250000f(x) = 21223780.22 x^-2.11Mass of Marker ProteinDisance Each Polypeptide Standard Migrated (mm)Mass of Each Polypeptide Standard (Daltons)Using the equation y=2E+07x^-2.111 and the provided list of molecular weights, with E representing the unknown mass and x being the distance traveled by the protein, E was foundto be 35,855 Daltons. This corresponds to the protein lactate dehydrogenase. Therefore, we canconclude that the marker protein is lactate dehydrogenase.Discussion:The data gathered from the denatured proteins was graphed using Excel. A power function graph was chosen over a log or linear because it fit the best. A linear graph wouldn’t work due to the non-constant change in mass from protein to protein. The log graph was to close to the axis as well as to extreme to account for the gradual curve that was needed. A power curve fit the data plot perfectly.The distance that the unknown marker protein traveled was measured to be 20mm, and this number was plugged into the equation Y=2E+07x^-2.111 as x to solve for E, which would bethe mass of the protein. E ends up being 35,855 Daltons, the same mass as lactate dehydrogenase.As for the casein protein, both formed a single band when denatured. Therefore, Casein is a monomer.Reference:UCM Bio 001 Lab 2 Analysis of Protein Size and Subunit Composition Using SDS-Polyacrylamide Gel Electrophoresis[1] Berenbaum, May, Craig Heller, David Hillis and David Sadava. “Studying Life”. Life: The Science of Biology. Ed. 9th . Ma, Boston; Sinauer Associates Inc., 2011. 42-49. Text.[2] Kresge, Nicole. “SDS-PAGE to Determine the Molecular Weight of Proteins: the Work of Klaus Weber and Mary Osbord.” SDS-PAGE to Determine the Molecular Weight of Proteins: The Work of Klaus Weber and Mary Osborn. The Journal of Biological Chemistry, 16 June 2006. Web.25 Sept.