Bio-Rad Experion Protein Analysis Kits - Manual (Page 35)

electropherogram. The corrected area of a peak is proportional to the amount of the protein
it represents in a mixture.
Percentage determination –– measures the percentage of each protein in a protein mixture
(% Total). This method is commonly used for determining protein content, protein purity, and
protein stability
Concentration determination –– provides the amount of the protein(s) in a protein mixture
rather than just a percentage of the total. There are several different ways that concentration
determination can be performed, and these methods provide more or less precision
depending on the type of internal standard used and the extent to which a calibration curve
is used
Relative quantitation –– Experion software uses an internal standard to estimate the
concentrations of sample proteins. Estimates are calculated by comparing the corrected
peak area of the sample peak to that of the internal standard in each sample well. The
internal standard can be either the upper marker (260 kD), which is included in the
Pro260 sample buffer, or a user-defined protein (10–<260 kD) added to each sample at
a known concentration.
Absolute quantitation –– Experion software can also create a calibration curve to use
for quantitation. To create the calibration curve, a defined protein calibrant at different
concentrations is separated in different sample wells. The corrected peak areas of the
different concentrations are compared to that of an internal standard (as with relative
quantitation, the upper marker or a user-defined protein can be used as the internal
standard). Experion software plots the resulting ratios as a function of protein
concentration, and the sample protein concentration is then determined from this
calibration curve.
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