Proteomics Lab Report

Proteomics is the study of proteomes, which are groups of proteins in living systems. It is used to examine when and where proteins are being expressed, rate of degradation, modifications, how they interact with other proteins and more. The goal in this lab was to determine the similarities and differences in muscle proteins among 5 species of fish using SDS-PAGE and Western blotting. First, proteins are separated based on size. Second, antibodies are used to detect the protein of interest. Lastly, a substrate that responds with an enzyme is used to view the antibody/protein complex.
Within a muscle tissue, there could be as many as 19 different protein types and the largest being actin and myosin. Actin and myosin can be found in all fish
SDS-PAGE is similar to DNA gel electrophoresis. They are both used to separate proteins by charge, in that positively charged molecules move towards the he negative electrode; negatively charged molecules move towards the positive electrode. The only difference is SDS is used to denature proteins and coat them so that they all carry negative charges although DNA is already negatively charged. But, protein can have numerous net charge, so it is essential that they are coated with SDS before it moves through the gel. Laemmli sample buffer is included in the SDS and the type of buffer used to dissolve protein. In addition, gels are already casted and prepped for use immediately and gel are made up of thin polyacrylamide layer sandwiched by two glass plates. Gels are also positioned vertically with wells at the top. Subsequently, gels are stained overnight using Coomassie Blue as oppose to ethidium bromide. SDS along with heat applied to the proteins from the fish samples, denatures the proteins original structures so that they become more linear. The dodecyl sulfate part of SDS gives the proteins a charge that is overall, negative. This negative charge allows the proteins to be separated according to their size. Figure 1. Is