BCA protein assay (reformatted!)

Shaun D. Black SHAUN%JASON.DECNET at relay.the.net
Wed Mar 2 13:05:08 EST 1994

     Take a look at Christia Stoscheck's article in Methods Enzymol.
182: 50-68 (1990).  It contains a wealth of practical information on
UV, Copper, Coomassie, BCA, and colloidal Gold protein assays.  It
is easy to follow her protocols for each assay.  The BCA assay begins
on p.60, as follows:

     Reagent A: 1g    Sodium bicinchoninate (BCA)
                2g    Sodium Carbonate
                0.16g Sodium tartrate
                0.4g  Sodium hydroxide
                Bring to 100 ml volume with water
                Adjust pH to 11.25 with 10 M NaOH

     Reagent B: 0.4g  Copper sulfate (pentahydrate)
                Bring to 10 ml with water

     Standard Working Reagent (SWR): Mix 100 vol of Reagent A with 
                2 volumes Reagent B
                SWR should be stable for 1 week and should be green.

Combine 1ml SWR and 20 uL of sample; mix.
Incubate 30 min at 60=B0C.
Read Absorbance at 562nm; readings stable for about 1 hr.

There is also a recipe given for a BCA micromethod, on p. 61.  Hope
this helps.  Cheers,  Shaun  (shaun%jason.decnet at relay.the.net)

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