Bio-Rad Protein Assay - Manual (Page 8)

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Fig. 2. Typical standard curve for the Bio-Rad Protein Microassay (1-20 µg/ml),
bovine gamma globulin (standard I), bovine serum albumin (standard II).
O.D.
595
corrected for blank. 1.25-25 µ g/ml x 0.8 ml = 1-20 µ g protein.
2.4 Microtiter Plate Protocols
The Bio-Rad Protein Assay can also be used with a microplate reader,
such as Bio-Rad's Model 450 and 3550 Microplate Readers. The linear
range of the Standard and Microassay procedures when used in the
microtiter plate format is slightly changed, since the ratio of sample to dye
is modified.
Standard Procedure for Microtiter Plates
1. Prepare dye reagent by diluting 1 part Dye Reagent Concentrate with
4 parts DDI water. Filter through a Whatman #1 filter (or equivalent)
to remove particulates. This diluted reagent may be used for about 2
weeks when kept at room temperature.
2. Prepare three to five dilutions of a protein standard, which is repre-
sentative of the protein solution to be tested. The linear range of this
microtiter plate assay is 0.05 mg/ml to approximately 0.5 mg/ml.
Protein solutions are normally assayed in duplicate or triplicate.
Microassay procedure
(1-20
µ g)
Protein ( µ g,ml)
BSA
IgG
O.D
. 595
2.5 5 7.5 10 12.5 15 17.5 20 22.5 25
0.1
0.2
0.3
0.4
0.5
0.6
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