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Biology-Related Homework Help Biochemistry Topic started by: keetner on Dec 3, 2012



Title: Protein concentration assays: Warburg/Christian vs Kalb/Bernlorh
Post by: keetner on Dec 3, 2012
I need clarification more than anything.

Warburg and Christian method measures nucleic acids and proteins at 260/280 nm, while the Kalb and Bernlorh method measures it at 230/260. I'm confused by how it works at 230/260 -- what is being measured at these two absorbances? Also, I read in a journal article that K/B improves on that of W/C. If this is the case, why don't we use it all the time, then?

Both the calorimetric assay of Lowry et al. (5) and the spectrophotometric method of Warburg and Christian (1) offer different advantages. The Lowry et al. procedure is sensitive and relatively immune to nucleic acid interference, while the Warburg and Christian assay is rapid and immune to interference by many chemicals that perturb the Lowry et al. assay. Our new spectrophotometric assay SPECTROPHOTOMETRIC PROTEIN ASSAY 371 combines the advantages of both these assays with regard to sensitivity, speed, and freedom from interference. (Kalb and Bernlohr, 1977)

But if this is the case, I would feel like we would ditch the Lowry assay entirely and use this guy all the time. But that can't be the case, can it? I'm just confused.

Any clarification would be greatly appreciated -- thanks!