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The equation at the right shows the
relationship between molar extinction
coefficient (
) and percent extinction
molar
coefficient (
1%).
To determine concentration (c) of a sample
in mg/mL, use the equation at the right and
a conversion factor of 10.
Tip: The NanoDrop One software includes
the conversion factor when reporting
protein concentrations.
Thermo Scientific
Conversions Between
(
) * 10 = (
molar
Example: To determine percent solution extinction coefficient
(
1%) for a protein that has a molar extinction coefficient of
-1
-1
43,824 M
cm
and a molecular weight (MW) of 66,400
daltons (Da), rearrange and solve the above equation as
follows:
1% = (
* 10) / (MW
molar
1% = (43,824 * 10) / 66,400 Da)
1% = 6.6 g/100 mL
Conversions Between g/100 mL and mg/mL
C
in mg/mL = (A /
protein
Example: If measured absorbance for a protein sample at
280 nm relative to the reference is 5.8 A, protein
concentration can be calculated as:
C
= (A /
1%) * 10
protein
C
= (5.8/6.6 g/100 mL) * 10
protein
C
= 8.79 mg/mL
protein
5
Protein Applications
Measure Protein A280
and
1%
molar
1%) * (MW
)
protein
)
protein
1%) * 10
NanoDrop One User Guide
75
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