Bradford Assay
Bradford Protein Assay Practical Report
1. Present your data (including raw data and calculated concentrations) for the protein standards in the form of a clear table. Give one example of how you calculated protein concentration. Do not forget a descriptive title and units (4marks)
Title either too long or not descriptive or absent
Your results are in duplicate & shouldn’t be referred to as ‘set1 & set2’ or ‘original’ and ‘duplicate’
Many of you think units of absorbance are nm but A has arbitrary
(ie no) units. nm indicates the max of the chromophore
Failure to give correct units in legends eg (ml) or (g/ml)
2. Plot a graph of absorbance against protein concentration by hand. The graph should have an appropriate title and clearly labelled axes. Staple graph to the completed proforma and the Life Sciences submission sheet (4 marks)
Mainly ok but both duplicate Abs- blank should be plotted and one line of best fit drawn through points.
Do not extrapolate beyond the highest standard, you have no evidence that Beer-Lambert’s Law applies at high A. Make sure you choose appropriate scale and use full scale deflection on A4 graph paper.
These types of graph are standard curves and that term should be in the title, remember we are not directly measuring the absorbance of protein, but a chromophore derived from the protein.
3. Present your data for unknown samples (including raw data and calculated concentrations of X &Y) in the form of a clear table. Do not forget title and units. (4 marks)
All data should be in one table but pay attention to typesetting and make sure that words/numbers are not split between 2 lines, this will lose marks.
Absorbance of blank must be subtracted from values for unknown as they also contain non-specific absorbance.
Many of you wrote dilutions incorrectly eg 1:2. The symbol : means ratio this actually means 1in 3. Either write as 1in 2 or 1:1
Never average absorbance-it’s not good practise (except for
1. Present your data (including raw data and calculated concentrations) for the protein standards in the form of a clear table. Give one example of how you calculated protein concentration. Do not forget a descriptive title and units (4marks)
Title either too long or not descriptive or absent
Your results are in duplicate & shouldn’t be referred to as ‘set1 & set2’ or ‘original’ and ‘duplicate’
Many of you think units of absorbance are nm but A has arbitrary
(ie no) units. nm indicates the max of the chromophore
Failure to give correct units in legends eg (ml) or (g/ml)
2. Plot a graph of absorbance against protein concentration by hand. The graph should have an appropriate title and clearly labelled axes. Staple graph to the completed proforma and the Life Sciences submission sheet (4 marks)
Mainly ok but both duplicate Abs- blank should be plotted and one line of best fit drawn through points.
Do not extrapolate beyond the highest standard, you have no evidence that Beer-Lambert’s Law applies at high A. Make sure you choose appropriate scale and use full scale deflection on A4 graph paper.
These types of graph are standard curves and that term should be in the title, remember we are not directly measuring the absorbance of protein, but a chromophore derived from the protein.
3. Present your data for unknown samples (including raw data and calculated concentrations of X &Y) in the form of a clear table. Do not forget title and units. (4 marks)
All data should be in one table but pay attention to typesetting and make sure that words/numbers are not split between 2 lines, this will lose marks.
Absorbance of blank must be subtracted from values for unknown as they also contain non-specific absorbance.
Many of you wrote dilutions incorrectly eg 1:2. The symbol : means ratio this actually means 1in 3. Either write as 1in 2 or 1:1
Never average absorbance-it’s not good practise (except for