Biuret Reagent - GCSE Biology Definition

Biuret Reagent is a chemical solution used to test for the presence of proteins in a sample. In GCSE Biology experiments, it helps identify proteins by changing colour from blue to purple when protein is present. This colour change occurs because the reagent reacts with peptide bonds, which link amino acids in a protein. A stronger purple colour indicates a higher protein concentration. The Biuret test is commonly used in food tests to investigate whether protein is amongst the biological molecules present in a sample.