Are Macromolecules Determine Peptide Bonds In Proteins?

Proteins are a multifarious group of macromolecules, which carry out many different functions within the human body. (Mbuthia, 2009). They are comprised of repeating units of amino acids held together by peptide bonds. As stated by Mbuthia, the Biuret reagent is a solution which aids scientists to conclude if there are any peptide bonds present within a sample, and thus, is used to determine protein existence within a substance. The Biuret assays depends on the presence of 2 or more peptide bonds in proteins. In an alkali environement, when a protein solution is given (Cu2+) Cupric ions, they will be reduced to (Cu+) copper cuprous, thus causing a Cu2+ - copper chelate complex, turning the soliution from blue to violet. (Dennison, 2013). The …show more content…
(Nakai & Modler, 1996). The intensity of the colour is proportional to the number of aromatic amino acids present, and reacting. Both methods a standard curve of BSA (bovine serum albumin), this being a quantitative means; a technique of plotting assay data that is used to deduce the concentration of unknown proteins. A curve is produced by plotting concentration on X-axis and Absorbance on Y-axis. The unknown concentration can be found by reading their absorbance y axis, until intersecting the standard curve, and then reading down the graph until intersecting the x axis. According to Beer-Lambert’s law there is a linear relationship between absorbance and concentration, of an absorbing species. (David, 2001). Hence, the standard curve should produce a linear function, however, at higher concentrations beer –lamberts law doesn’t hold; and a slightly non-linearity may be seen. Therefore, the aim of this practical is to use the standard curve to determine the apparent protein concentration of both Gelatin and Y-Globulin and to compare this concentration with their known