In a biology lab that I conducted, glucose did not react with the Biuret reagent. Does this mean that glucose does not contain proteins?
Biuret reagent detects the presence of peptide bonds. These are present in proteins, which are made up of multiple peptides joined together. Hence biuret reagent reacts with protein.
Glucose is a sugar – more specifically a monosaccheride i.e. a single unit sugar. It does not have any peptide bonds – that is why it does not react.
Does Glucose Contain Protein
yup…u r right…
The biuret test is a chemical test used for detecting the presence of peptide bonds. In the presence of peptides, a copper(II) ion forms a violet-colored complex in an alkaline solution
The Biuret reaction can be used to assay the concentration of proteins because peptide bonds occur with the same frequency per amino acid in the peptide. The intensity of the color, and hence the absorption at 540 nm, is directly proportional to the protein concentration, according to the Beer-Lambert law.
In spite of its name, the reagent does not in fact contain biuret ((H2N-CO-)2NH). The test is so named because it also gives a positive reaction to the peptide bonds in the biuret molecule.
The biuret reagent is made of potassium hydroxide (KOH) and hydrated copper(II) sulfate, together with potassium sodium tartrate. The reagent turns from blue to violet in the presence of proteins, blue to pink when combined with short-chain polypeptides.
proof for ur point..of non nvolvement of glucose in biuret..
You are correct. Glucose doesn’t contain proteins.
Glucose is a sugar, while a protein are linked up amino acids .