P2. PROTEINS Flashcards
complex macromolecule made up of amino acids.
Proteins
the 20 amino acids varies in…
numbers & sequence
Amino Acids contains what groups?
COOH [carboxyl group]
-NH2 [amino group]
-R group [the side chain]
the building block of proteins?
amino acids
2 types of test used in Proteins?
Biuret Test
Hopkin Cole’s Test
- general test/semi-quantitative test.
- test for the detection of peptide bonds/peptide linkages
Biuret Test
Cupric ions [in an alkaline medium] forms a violet complex with [nitrogen] peptide bonds in the protein.
Biuret Test
TRUE OR FALSE?
All proteins contain peptide linkages.
True
Reagents used in Biuret Test:
10% NaOH
Copper Sulfate
The violet positive result in biuret test indicates a percentage of what?
5% Albumin
TRUE OR FALSE:
COLOR REACTION in Biuret Test depends on the presence peptide bonds/linkages.
True
DARKER COLOR in Biuret test means?
MANY PEPTIDE LINKAGES
LIGHTER COLOR in Biuret test means?
FEW PEPTIDE LINKAGES
Pink color in the Biuret Test means?
their is a presence of peptide linkages.
UREA & ALANINE in Biuret Test results?
no visible reaction/
no visible result
- indole ring of tryptophan combines with aldehydes
e.g formaldehyde in the presence of conc. Sulfuric acid to form a violet-colored compound
Hopkin’s Cole Test
Reagents used in Hopkin’s Cole Test:
Hopkin Cole’s Reagent
Composition of Hopkin’s Cole Rgt.:
Formaldehyde
Mercuric Sulfate
Sulfuric Acid
chemical composition of the Hopkin’s Cole Rgt. that causes a MILD OXIDATION of indole group of tryptophan [which condenses w/ aldehyde to give a colored complex].
Mercuric Sulfate
Result of Hopkin’s Cole Test: It forms a ____ and a ____ forms at the junction of the two layers.
- separate layer
- deep violet or purple ring
if there is a purple ring, there is a?
tryptophan
- there is a presence of indole ring in its structure
- the only one who will give a deep violet/purple ring because they have an indole group
Tryptophan
Substances in Hopkin’s Cole Test wherein TRYPTOPHAN IS ABSENT:
Albumin
Gelatin
Tyrosine
Results of Albumin, Gelatin, and Tyrosine in Hopkin’s Cole test:
- (-) indole ring
- no visible result/ no visible reaction
