Lab Report: Total Protein Determination
Cellular Biology

Abstract The lab report assesses how to determine the total amount of proteins in a substance. By applying the correct procedures individuals are able to discover how healthy blood cells and tissues are. Higher levels of protein can indicate infections such as hepatitis or HIV, while lower levels can entail haemorrhaging or malnutrition. Through application of solutions in a spectrophometer individuals can define the concentration of a material due to Beer’s law. The law states that the concentration of a substance is directly proportional to the amount of light it absorbs. The total number of proteins in a substance can help decide what the state is of an individual’s blood cells and tissues are.

Introduction The total protein determination experiment helps scientists determine what disease an individual may have. For example higher then average protein found in blood or tissue can indicate HIV or hepatitis, while a lower then average number of proteins can indicate haemorrhaging. There are many different methods to establish how many proteins are in a substance. These methods have difference measures of liquid such as “5 cc. of plasmid per each constitution of the blood determined,” while others only required “0.5 cc. of plasmid or serum” (Howe, P., 1921). The total protein determination can also be used to determine what blood type an individual is. The amount of proteins, also called antigens, is different for each blood type (Bianco, C., n.d.). The total protein determination is established by placing the solution through a spectrometer. The spectrometer reveals how much light a substance is able to absorb. According to Beer’s law the amount of light that a substance is able to absorb is directly related to the substances concentration of grams per millilitres. This implies that if we are able to determine the amount of light absorbency we are able to discover the amount of protein in a given substance. To determine the amount of protein in a substance a standard curve is created using the known data. The known substances absorbency and concentration of grams per millilitre are plotted on the graph. Once the known substance have been plotted a line is drawn through the points. The known absorbency of the unknown substance is then used to determine the concentration in the substance. Where the absorbency of the substance is across from the standard curve, the concentration of grams per millilitres directly below the line is the concentration of the unknown substance. The total protein determination is an experiment that helps to determine how many proteins are in a unknown substance. The number of proteins in a sample helps to discover many different things about an individual’s body.
Materials
The materials used to determine the total number of proteins in the unknown substance are itemized below:
2 Graduated/Mohr Pipettes
Rubber Bulb
Semi Automated/Eppendorf Pipette with tips
Paraphilm
9 test tubes/cuvettes (properly labeled)
Permanent Marker
Lab coat, Gloves and Goggles for safety
Spectrometer
0.9% NaCl
Biuret Regent
Method
Each student was able to apply their knowledge of the spectrometer and pipetting in order to determine the total protein in the substances. By following a multitude of steps. Each individual was able to determine the total amount of protein in the unknown substance. The steps I followed are listed below:
1. Set the wavelength on the spectrophometer at 540nm. Allow the spec to warm up for at least 15 minutes.
2. Label 9 test tubes/cuvettes – one blank, two cuvettes for each S1, S2, S3, and U.
3. Into each tube, pipette 1ml of 0.9% NaCl using the 10ml volumetric pipette.
4. Using the semi-automated (Eppendorf) pipette, add 20ul of standard or unknown to the appropriate tube. Be sure to mix the specimens well before pipetting.
5.