ThermoFisher Scientific NanoDrop Eight, Руководство пользователя

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5
Protein Applications
Measure Protein A280
Thermo Scientific NanoDrop Eight User Guide 47
Tip Ideally, the extinction coefficient should be determined empirically using a
solution of the study protein at a known concentration using the same buffer.
Setting Available Options
Mass Ext.
Coefficient
(L/gm-cm)
Description
Sample
type
a
1 Abs = 1 mg/mL General reference Recommended when extinction coefficient is
unknown and rough estimate of protein
concentration is acceptable for a solution with
no other interfering substances. Assumes
0.1% (1 mg/mL) protein solution produces
1.0A at 280 nm (where pathlength is 10 mm),
i.e.,

1% = 10.
BSA 6.7 Calculates BSA (Bovine Serum Albumin)
protein concentration using mass extinction
coefficient (

) of 6.7 L/gm-cm at 280 nm for
1% (i.e., 10 mg/mL) BSA solution. Assuming
MW is 66,400 daltons (Da), molar extinction
coefficient at 280 nm for BSA is approximately
43,824 M
-1
cm
-1
.
IgG 13.7 Suitable for most mammalian antibodies (i.e.,
immunoglobulin G or IgG). Calculates protein
concentration using mass extinction
coefficient (

) of 13.7 L/gm-cm at 280 nm for
1% (i.e., 10 mg/mL) IgG solution. Assuming
MW is 150,000 Da, molar extinction coefficient
at 280 nm for IgG is approximately
210,000 M
-1
cm
-1
.
Lysozyme 26.4 Calculates lysozyme protein concentration
using mass extinction coefficient (

) of
26.4 L/gm-cm at 280 nm for
1% (i.e., 10 mg/mL) lysozyme solution.
Assumes molar extinction coefficient for egg
white lysozyme ranges between
36,000 M
-1
cm
-1
and 39,000 M
-1
cm
-1
.