[brasarehot]

I'm trying to figure out this homework problem...
Calculate the protein concentration in a sample that has absorption 0.98 at 280 nm and 0.6 at 260 nm.
ANSWER:C(mg/ml) = 1.55 x A280 - 0.76 x A260 = 1.55 x 0.98 - 0.76 x 0.6 = 1.063.

Where does 1.55 and 0.76 come from?
How do you approach this problem with OD=epsilon(l)(C)?
Are 0.98 and 0.6 optical densities?

Thanks for the help

[Borek]

There must be some context to this question, otherwise numbers don't make any sense. But I guess they were introduced in some way earlier, either in a book or in a lecture.

[Babcock_Hall]

I might hazard a guess.  Impure preparations of proteins may have nucleic acids as one of the impurities.  Although proteins usually absorb maximally around 280 nm, nucleic acids absorb strongly around 260.  Therefore, one must find a way to factor out the nucleic acid contribution. The Warburg-Christian equation is that protein (mg/mL) = 1.55A(280) - 0.76A(260).