Question

Need help ASAP!

Please explain (not too long, straight to the point) what happens/results during the denaturation test with egg albbumin and heat, egg albumin and 95% ethanol, and egg albumin and FeCl3. What is the result of glycine, proline, and egg albumin during the ninhydrin test.

Answer 1

The most obvious change in egg albumin brought about by the action of heat, alcohol and other reagents is the total loss of solubility in the region of the iso electric point. also during denaturation test of egg albumin by heat there is also change in the pH of the egg albumin solution.

Ninhydrin (2,2-dihydroxyindane-1,3-dione) is a chemical used to detect ammonia or primary and secondary amines. When reacting with these free amines, a deep blue or purple color known as Ruhemann's purple is produced. Ninhydrin is most commonly used to detect fingerprints, as the terminal amines of lysine residues in peptides and proteins sloughed off in fingerprints react with ninhydrin.

Amino acids contain a free amino group and a free carboxylic acid group that react together with ninhydrin to produce a coloured product. When an amino group is attached to the first, or alpha, carbon on the amino acid’s carbon chain, the amino group’s nitrogen atom is part of a blue-purple product Proteins also contain free amino groups on the alpha carbon and can react with ninhydrin to produce a blue-purple product.

Amino acids that have secondary amino group attachments also react with ninhydrin. However, when the amino group is secondary, the condensation product is yellow.

glycine react with ninhydrine form purple colour

Proline react with ninhydrine form yellow colour

Egg albumin react with ninhydrine forms intense blue colour