NanoPhotometer
®
NP80/N60/N50/C40
User Guide Version 3.1
62
Lowry Assay
Method is based on the Biuret reaction. Under alkaline conditions the divalent copper ion forms
a complex with peptide bonds in which it is reduced to a monovalent ion. Monovalent copper ion
and the radical groups of tyrosine, tryptophan, and cysteine react with Folin reagent to produce
an unstable product that becomes reduced to molybdenum/tungsten blue. The bound reagent
changes color from yellow to blue. This binding is compared with that obtained with a standard
protein at 750 nm; this is usually BSA (bovine serum albumin).
Note:
Detailed protocols are customarily supplied with these assay kits, and must be closely
followed to ensure that accurate results are obtained.
M
EASUREMENT
P
ROTOCOL
1. Select protein assays icon from home screen.
2.
To change between NanoVolume and cuvette application, use the
Change to Cuvette/NanoVolume button below the parameter area
(NP80/C40 only).
3. To change the assay type click on Bradford and a list with available options opens on the
right side.
Options are: BCA Assay, Biuret Assay, Bradford Assay, Lowry Assay (not for N50)
4.
For Cuvette Application:
Select the path length depending on the used cuvette.
Options are: 0.5 mm, 1 mm, 2 mm, 5 mm and 10 mm
