Why Measure Protein Concentration. Protein Analysis-Determination of Protein Concentration When purifying a protein we need to know how much protein is present in our samples. Another important issue pertains to the purity of protein samples and information about their spectral properties including their extinction coefficients. The protein concentration of CSF usually is more than 100-fold lower than for plasma and methods with greater sensitivity or increased specimen volume are required for measuring total serum or plasma protein. In general you measure the absorbance of a series of known concentrations of a standard protein generally BSA and create a standard curve.
This method requires at least 1-20mg of protein a relatively large amount. If you are characterizing the amino acids in the fungal cell then as far as I know measurement of protein concentration is essential because deficiencies in these nutrients can reduce desired. Just as various as the methods to measure protein concentration are the reasons why proteins need to be quantified in a life science laboratory. The relationship of absorbance to protein concentration is linear. For workflows utilizing proteomics using mass spectrometry it is important to measure peptide concentration following protein digestion enrichment andor C18 clean-up steps in order to normalize sample-to-sample variation. The samples contain a mixture of proteins and are lysates of cultured cells cell compartments or tissues.
The protein concentration of an unknown is determined by comparing the color produced by the unknown solution with the color produced by solutions of known protein the standard curve.
Each method is best in different situations. Because different proteins and nucleic acids have widely varying absorption characteristics. The intensity of the color is indicative of protein concentration. Just as various as the methods to measure protein concentration are the reasons why proteins need to be quantified in a life science laboratory. In particular for experiments utilizing isobaric labeling it is critical to ensure that equal amounts of sample are labeled before mixing in order to have accurate results. Concentration of protein present in the sample.