Figure 5. Bradford Assays of cat food.

Samples of cat food were hydrolyzed with proteinase K or acid, prior to testing, since attempts using untreated samples were unsuccessful due to the difficulty in dissolving the cat food. (A) Food treated with proteinase K. The calculated percentage of protein in the cat food was about 1%, considerably less than the manufacturer’s claim of 30%. (B) Bradford assay of acid treated cat food. The cat food was not fully dissolved for this test, but its calculated concentration was 3-6% for the HCl treated and 1% for the H₂SO₄ treated food.