On Monday, April 8, 2013 4:57:29 AM UTC-4, Sudheer Sangeetham wrote: > Hello all > > > > I would like to quantify the protein concentration. I checked the nanodrop > > manual in that they have given that I can estimate the protein by measuring > > directly at 280 nm by giving extinction coefficient value without doing > > bradford or lowry methods. I would like to choose measuring the protein > > concentration directly. Because I need to handle many samples all the time, > > so it is difficult for me to do bradford or lowry methods all the time. So > > How far is correct if I estimate the protein concentration directly? please > > give me your suggestion > >
Do you have a mixture of proteins, or a purified protein of known extinction coefficient? The Nanodrop can be run in several modes (or at least some models can). For unknown mixtures, the best you can get is only a rough estimate (typically by assuming that a A280 = 1 corresponds to 1 mg/ml). If you have a pure characterized protein, some models will let you input the extinction coefficient and calculate it exactly. If you don't know the extinction coefficient but the sequence is known, there are online tools to estimate one, e.g.: http://web.expasy.org/protparam/ Nick -- Nick Theodoreakis _______________________________________________ Methods mailing list [email protected] http://www.bio.net/biomail/listinfo/methods
