Bradford Protein Assay Essay

803 Words Feb 10th, 2013 4 Pages
An Le
Foundation Biology lab
BRADFORD PROTEIN DISCUSSION ESSAY
The appearance of blue color showed the present of protein in the BSA dilutions. The more diluted the solution was, the less blue it was. The R2 value of the standard curve of BSA dilution was obtained to be 0.9972, which is close to 1. The closer to 1 the R2 value was, the more accurate the linear portion was. The error percentage of each unknown was large: 25.9% for skim milk, 95% for soy sauce, and 64.7% for egg white. The vast difference between the theoretical protein concentration and experimental protein concentration of the unknowns showed that Bradford Protein Assay must have limitations. The Coomassie dye only interacts with certain amino acids such as:
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That means there were certain minor factors that influenced on the instrument. Bradford protein assay was used to determine protein concentration in several samples. Moreover, Bradford protein assay was not able to detect the presence of melamine in the food because the experimental protein concentration was obtained to be -0.005 mg/ml, which is invalid. Bradford protein assay didn’t interact with melamine even though it contains so many amino groups (Field and Field 2010). Melamine is not protein because it doesn’t have either carboxyl groups or functional groups, which are components of an amino acid. At high level, melamine can be toxic by combining with cyanuric acid to form insoluble crystals, which lead to the formation of kidney stones (Eufic, n.d.). Melamine amounts make the amount of protein look higher than they really are when tests that are used to detect nitrogen are used (Science Daily, 2009). Even though melamine has been notified to be toxic, there are still numbers of melamine-contaminated food in the market because the melamine tests are way to expensive to apply on every single product and take to much time to proceed. In future, to test the accuracy of the Bradford protein assay, more trials will be conducted with different proteins such as: protein shake, chicken broth and 2% whole milk. Since the disability of detecting of the Bradford protein assay, some other methods
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