How do you carry out a simple laboratory test for a protein?

To carry out a simple laboratory test for a protein, you can use the Biuret test. First, dissolve the sample in a small amount of water, then add an equal volume of Biuret reagent, which contains copper sulfate. If proteins are present, the solution will change color to violet due to the formation of a complex between the copper ions and the peptide bonds in the protein. The intensity of the color can also provide a rough estimate of protein concentration.