Lesson 1 Proteins 1 Flashcards
(30 cards)
a dipeptide, a sweetener that has no sugar component
Aspartame
– a tripeptide
– an antioxidant that prevents damage to cellular components caused by free radicals.
Glutathione
the main group of milk proteins found in different ratios in various milk species.
Caseins and whey proteins
General test for proteins, detecting peptide bonds
Biuret Test
What is the negative indicator of the Biuret Test
blue
What is the chemical reaction involved in the Biuret Test
The reaction is a formation of complex between copper and oxygen and between copper and nitrogen
What were the experimental results for the Biuret test?
Results showed purple color egg albumin and very light purple for milk
General test for proteins except proline (yellow)
Ninhydrin test
What is the Chemical Reaction for the Ninhydrin test?
Ninhydrin oxidizes the amino group in the amino acid and proceeds the chemical reaction forming a complex called Ruhemann’s complex which give the deep blue color.
Ninhydrin test results show
All samples showed a deep blue coloration
Test for indole group, tryptophan
Hopkins-Cole Test
Hopkins-Cole Test: The indole group of tryptophan reacts with ______ in the presence of concentrated H2S04 to give a ________.
glyoxylic acid, purple color
Experiment Results of Hopkins-Cole Test
Only egg albumin showed distinct purple color in the junction between reagents
Test for activated aromatic rings, Tyrosine and tryptophan
Xanthoproteic Test
what are the reagents for Xanthoproteic Test
Reagents: Conc. Nitric Acid, ammonium hydroxide
Positive Result for Xanthoproteic test:
Positive result: Yellow or dark orange solution or precipitate
When the sample is treated with a ______ it undergoes nitration with the aromatic amino acids such as ________ and forms a ______
concentrated nitric acid, tyrosine and tryptophan, yellow color
Why wont Phenylalanine react in the Xanthoproteic test?
It is not an activated benzene ring so it will not react
What are the results for the Xanthoproteic test?
Only the egg and milk samples exhibit yellow coloration and formation of principates
Test for guanidine group, arginine
Sakaguchi Test
Reagents for Sakaguchi test
Reagent: α-Naphthol and a drop of sodium hypobromite
Positive indicator for Sakaguchi
Positive Result: red-colored complex solution
In the Sakaguchi reaction, _______ of sodium hypochlorite oxidizes the _______ group in arginine to give a red complex
Bromine water, guanidinium
Reagent for Ninhydrin test
Ninhydrin
