Biology Stack Exchange is a question and answer site for biology researchers, academics, and students. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

As I know, $Cu(OH)_2$ $+$ Protein $\rightarrow$ Purple. So why not use $Cu(OH)_2$ as dye in protein electrophoresis?

share|improve this question
May be the OH-group changes the summational charge of the protein (which is very important for the separation), as by adding the compound, we change pH. Still, copper is used in electrophoresis, but as CuCl2. – Stella Dimitrova Jun 28 '13 at 17:29

Copper hydroxide does not dissolve very well in water, which means you will have trouble soaking them into your gels.

Also, even if you managed to add enough copper hydroxide beforehand (in the wells), it is unlikely that the copper(II) ions, if any existes, will travel along with the protein due to its size. (Copper hydroxide itself does not have any charge.)

As for the paper Stella mentioned, the copper salts are used after electrophoresis to produce a negative image, which is exactly what you cannot do with copper hydroxide.

share|improve this answer
  1. Protein electrophoresis is often done in an alkaline pH (8.6), which is not exactly nice if you want to use $Cu(OH)_2$.
  2. If you need quantitation, you can use Coumassie blue or Amido black. If you want sensitivity you can use silver. These existing stuff are quite OK.
share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.