M7 Flashcards
____ and ____ are formed when amino acids are joined together by amide bonds
Peptides and Proteins
___ is called also peptide bond
Amide bond
___ has 2 amino acids joined together by one peptide bond
Dipeptide
___ have many amino acids
Polypeptide
___ has more than 40 amino acids
Protein
_____ are formed by a condensation reaction
Peptide bonds
___ are joined together and water is released
Amino Acids
What is the formation of polypeptides?
- Remove oxygen from the precedent amino acid and two hydrogens from the subsequent amino acid
- Place the two groups next to each other
General test for identification of proteins
Biuret test
In the presence of _____ _____, Cu2+ ions forms as a complex with the peptide bonds due to the unshared electron pairs in nitrogen, and the oxygen in water
Alkaline Solution
Biuret Test: Gelatin
Result: ?
Purple Solution
Proteins (peptide bonds) are present
Biuret Test: Egg Albumin
Result: ?
Purple Solution
Proteins (peptide bonds) are present
Biuret Test: Glycine
Result: ?
No Reaction
Biuret Test: Antibiotic Solution
Result: ?
Pink Solution
Proteins (peptide bonds) are present
Test for the presence of a-amino acids in proteins
Ninhydrin Test
___ causes oxidative decarboxylation and deamination of a-amino acids producing an aldehyde, carbon dioxide, and ammonia
Ninhydrin
Ninhydrin is reduced to _____ which reacts with the liberated ammonia and another molecule of ninhydrin
Hydrindantin
Ninhydrin Test: Egg Albumin
Result: ?
Deep Blue Solution
Presence of alpha-amino acid
Ninhydrin Test: Gelatin
Result: ?
No Reaction
Ninhydrin Test: Alanine
Result: ?
Deep Blue Solution
Presence of alpha-amino acid
Test for the presence of aromatic amino acids
Xanthoproteic Test
Amino acids containtin aromatic nucleus react with concentrated HNO3 to from _____-_____ complex on heating.
It changed to ____-____ _____ when excess NaOH is added
Yellow-coloured Complex;
Orange-Red Colour
Xanthroproteic Test: Egg Albumin
Result: ?
Dark Yellow Solution
Presence of arom
Xanthroproteic Test: Tyrosine
Result: ?
Orange Red Solution
Xanthroproteic Test: Alanine
Result: ?
No Reaction
Xanthroproteic Test: Phenylalanine
Result: ?
No Reaction
Test for phenolic compounds
Millons Test
Millons test is also used to setect the presence of ______ - the only amino acid containing a phrnol group
Tyrosine
Tyrosine is the first nitrated by nitric acid in the test solution, then the nitrated tyrosine complexes ______ and ______ in the solution to form either a ______ or _____
Mercury (I) and Mercury (II)
Red Precipitated or Red Solution
Millon’s Test: Phenol
Result: ?
No Reaction
Millon’s Test: Phenylalanine
Result: ?
No Reaction
Millon’s Test: Tyrosine
Result: ?
Faint Red Precipitate
Millon’s Test: Casein
Result: ?
No Reaction
Test for the presence of tryptophan
Hopkin’s Cole Test
The inly amino acid containing an indole group
Tryptophan
The indole reacts with ____ ____ in the presence of a strong acid to form a _____ ______ product
Glyoxylic Acid
Violet Cyclic product
Hopkins Cole Test: Albumin
Result: ?
Violet Ring
Hopkins Cole Test: Casein
Result: ?
No Reaction
Hopkins Cole Test: Gelatin
Result: ?
No Reaction
Hopkins Cole Test: Tryptophan
Result: ?
Violet Ring
Test for the presence of cysteine or cystine
Lead Sulfide Test
The organic sulfur in cystein or cystine is released as ______ - ____ which from lead sulfide
Inorganic S-8 ions
Positive result of Lead Sulfide Test is the formation of ____ / ____ _______
Black or Brown Precipitate
Lead Sulfide Test: Albumin
Result: ?
Black Solution
Lead Sulfide Test: Tyrosine
Result: ?
No Reaction
Lead Sulfide Test: Casein
Result: ?
No Reaction
Positive result of Biuret Test
Purple / Pink Solution
Positive Result of Ninhyrin Test
Deep Blue Solution
Positive result of Xanthroproteic Test
Dark-Yellow / Orange-Red Solution
Positive result of Millon’s Test
Red Precipitate or Red Solution
Positive Result of Hopkins Cole Test
Violet Ring
Positive Result of Lead Sulfide Test
Black / Brown Solution
