18 Questions
What is the purpose of Millon's test?
To detect the presence of tyrosine in proteins
What is the composition of Millon's reagent?
Mercuric nitrate and mercurous nitrate dissolved in concentrated nitric acid
What happens to the tyrosine molecule during Millon's test?
It forms complexes with heavy metals like mercury
Is Millon's test specific for detecting tyrosine in proteins?
Yes, it is specific only for tyrosine detection
What is the color of the precipitate or solution formed during Millon's test?
Red-colored
Which group of compounds does Millon's test specifically detect?
Compounds containing the phenol group
Which color complex is formed when ninhydrin reacts with α-amino groups of proteins and amino acids?
Violet-pink
What color do nitrated products of aromatic rings on the side chains of proteins or free amino acids appear as?
Yellow
In Millon's test, what color does the solution turn into when made with basic sodium hydroxide?
Red-brown
Which protein group specifically answers the Xanthoproteic test?
Proteins containing a phenol group in the side chain
What is the color of the complex formed in the Hopkins-Cole test upon reaction with glyoxylic acid and concentrated sulfuric acid?
Violet
What kind of product does the presence of nitric acid lead to in proteins or free amino acids?
Yellow-colored complex
What color complex is typically formed when α-amino acids react with ninhydrin?
Blue-purple
What color do nitrated products of aromatic rings on the side chains of proteins or free amino acids appear as in solution?
Yellow
What is the purpose of Millon's test for proteins?
Specific detection of tyrosine
What is the color of the complex formed in the Hopkins-Cole test upon reaction with glyoxylic acid and concentrated sulfuric acid?
Violet
What happens to the color of the solution in Millon's test when it is made with basic sodium hydroxide?
Becomes more intense and ranges from yellow to orange to brown
What kind of product is formed when aromatic rings on the side chains of proteins or free amino acids are treated with concentrated nitric acid?
Yellow nitrated product
Study Notes
Millon's Test
- Purpose: To detect the presence of tyrosine in proteins
- Composition of Millon's reagent: Mercury(II) sulfate and sulfuric acid
- Tyrosine molecule: Forms a red precipitate when treated with Millon's reagent
- Specificity: Millon's test is not specific for tyrosine and can also detect other phenolic compounds
Reaction Products
- Color of the precipitate or solution formed: Red
- Compounds detected: Phenolic compounds, including tyrosine
- Color complex formed with ninhydrin: Purple (with α-amino groups of proteins and amino acids)
- Color of nitrated products of aromatic rings: Yellow
Chemical Reactions
- Reaction with basic sodium hydroxide: Solution turns red
- Reaction with glyoxylic acid and concentrated sulfuric acid (Hopkins-Cole test): Forms a purple complex
- Reaction with nitric acid: Forms a yellow nitrated product
Learn about Millon’s Test, an analytical method used to detect the amino acid tyrosine by nitrification of the phenol group and formation of complexes with heavy metals. Understand its specificity and its application in identifying tyrosine in proteins.
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