University:
Liberty University
Course:
BIOM 500 | Introduction to Biomedical Sciences
Academic year:

2024
Views:

59

Pages:

5
Author:

Sheha A.

Biuret Test Test is a general test for protein as it is answered by all proteins Procedure: Copper sulphate is added to protein Presence of NaOH Observation: A violet color is obtained Principle: Cupric ions in alkaline medium form a violet colored complex with peptide bond nitrogen of protein. The minimum requirement for the test result is the presence of at least two peptide bonds in the molecule. Biuret test is specific for -CO-NH- bond Diagrams: -ve Biuret Test Blue color (protein absent) +ve Biuret Test Purple color (protein present) Ninhydrin Test It is a general test for detection of a compound having the α-amino acid group. This is a most sensitive test for amino acid. Procedure: Freshly prepared ninhydrin solution is added to amino acids/protein solution. Observation: Violet color is obtained. Principle: Ninhydrin reacts with α-amino group of protein to give blue or purple colored complex called Ruhemann's purple. Ninhydrin Test The image illustrates the results of a Ninhydrin test, a chemical test used to detect amino acids. Negative Ninhydrin Test: Appearance: A test tube with a clear solution. Interpretation: Amino acid is absent. Positive Ninhydrin Test: Appearance: A test tube with a purple-colored solution. Interpretation: Amino acid is present.