Experiment No. 2 AMINO ACIDS AND PROTEINS Data Solubility in water Sample Solubility (Soluble, Partially Soluble, Insoluble) Color with red litmus paper Color with blue litmus paper Is the solution acidic, basic, or neutral? alanine glutamic acid arginine albumin Color Reactions of Amino Acids Ninhydrin Test Color of Ninhydrin solution: ___________________________________ Sample Color original solution Color with Ninhydrin Color after 10 min. alanine glycine glutamic acid tyrosine albumin Biuret Test Color of 3% CuSO4 solution: _____________________________________ Sample Color of original solution Color after NaOH/CuSO4 casein alanine albumin gelatin distilled water Molisch Test Color of Molisch reagent: _____________________________________ Sample Color of original solution Color after Molisch Reagent Color at the interface glutamic acid casein gelatin Xanthoproteic Test Color of concentrated HNO3: ___________________________________ Sample Color of original solution Color after HNO3 Color after NH4OH glutamic acid tyrosine casein albumin gelatin Millon’s Test Color of Millon’s reagent: _____________________________________ Sample Color of original solution Color after Millon’s Reagent Color after 5 min. glutamic acid tyrosine casein albumin gelatin Test for Sulfur Color of lead acetate solution: __________________________________ Sample Color of original solution Color after NaOH Color after lead acetate glutamic acid cysteine casein albumin Sakaguchi Test Color of alpha-napthol solution: _________________________________ Sample Color of original solution Color after NaOH/ alpha-napthol Color after hypochlorite/urea arginine glutamic acid casein albumin Coagulation of Proteins Observation fresh egg albumin egg albumin after heating egg albumin + nitric acid egg albumin + ethyl alcohol Precipitation by Heavy Metals Observation fresh egg albumin egg albumin + lead acetate egg albumin + mercury (II) chloride egg albumin + silver nitrate Precipitation by Alkaloidal Agents Observation fresh egg albumin egg albumin + tannic acid egg albumin + picric acid egg albumin + trichloroacetic acid Questions What is the positive result to the following tests? Ninhydrin Test: _______________________________________________ Biuret Test: _______________________________________________ Xanthoproteic Test: _______________________________________________ Millon’s Test: _______________________________________________ Test for Sulfur: _______________________________________________ Sakaguchi Test: _______________________________________________ What sample show a positive result with the Molisch Test? Why did this sample give a positive result? _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ What is the chemical basis of the Xanthoproteic Test? Give the chemical reaction involved. _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ Egg white and milk are used as antidotes for heavy metal poisoning. Explain. _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ According to advertisements, commercial shampoo or conditioner contains ‘‘protein.’’ Suggest a test that could be done on the product to check this claim? Explain your answer. _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________
Experiment No. 2
AMINO ACIDS AND PROTEINS
- Data
- Solubility in water
|
Sample |
Solubility (Soluble, Partially Soluble, Insoluble) |
Color with red litmus paper |
Color with blue litmus paper |
Is the solution acidic, basic, or neutral? |
|
alanine |
|
|
|
|
|
glutamic acid |
|
|
|
|
|
arginine |
|
|
|
|
|
albumin |
|
|
|
|
- Color Reactions of Amino Acids
- Ninhydrin Test
Color of Ninhydrin solution: ___________________________________
|
Sample |
Color original solution |
Color with Ninhydrin |
Color after 10 min. |
|
alanine |
|
|
|
|
glycine |
|
|
|
|
glutamic acid |
|
|
|
|
tyrosine |
|
|
|
|
albumin |
|
|
|
- Biuret Test
Color of 3% CuSO4 solution: _____________________________________
|
Sample |
Color of original solution |
Color after NaOH/CuSO4 |
|
casein |
|
|
|
alanine |
|
|
|
albumin |
|
|
|
gelatin |
|
|
|
distilled water |
|
|
- Molisch Test
Color of Molisch reagent: _____________________________________
|
Sample |
Color of original solution |
Color after Molisch Reagent |
Color at the interface |
|
glutamic acid |
|
|
|
|
casein |
|
|
|
|
gelatin |
|
|
|
- Xanthoproteic Test
Color of concentrated HNO3: ___________________________________
|
Sample |
Color of original solution |
Color after HNO3 |
Color after NH4OH |
|
glutamic acid |
|
|
|
|
tyrosine |
|
|
|
|
casein |
|
|
|
|
albumin |
|
|
|
|
gelatin |
|
|
|
- Millon’s Test
Color of Millon’s reagent: _____________________________________
|
Sample |
Color of original solution |
Color after Millon’s Reagent |
Color after 5 min. |
|
glutamic acid |
|
|
|
|
tyrosine |
|
|
|
|
casein |
|
|
|
|
albumin |
|
|
|
|
gelatin |
|
|
|
- Test for Sulfur
Color of lead acetate solution: __________________________________
|
Sample |
Color of original solution |
Color after NaOH |
Color after lead acetate |
|
glutamic acid |
|
|
|
|
cysteine |
|
|
|
|
casein |
|
|
|
|
albumin |
|
|
|
- Sakaguchi Test
Color of alpha-napthol solution: _________________________________
|
Sample |
Color of original solution |
Color after NaOH/ alpha-napthol |
Color after hypochlorite/urea |
|
arginine |
|
|
|
|
glutamic acid |
|
|
|
|
casein |
|
|
|
|
albumin |
|
|
|
- Coagulation of Proteins
|
|
Observation |
|
fresh egg albumin |
|
|
egg albumin after heating |
|
|
egg albumin + nitric acid |
|
|
egg albumin + ethyl alcohol |
|
- Precipitation by Heavy Metals
|
|
Observation |
|
fresh egg albumin |
|
|
egg albumin + lead acetate |
|
|
egg albumin + mercury (II) chloride |
|
|
egg albumin + silver nitrate |
|
- Precipitation by Alkaloidal Agents
|
|
Observation |
|
fresh egg albumin |
|
|
egg albumin + tannic acid |
|
|
egg albumin + picric acid |
|
|
egg albumin + trichloroacetic acid |
|
- Questions
- What is the positive result to the following tests?
- Ninhydrin Test: _______________________________________________
- Biuret Test: _______________________________________________
- Xanthoproteic Test: _______________________________________________
- Millon’s Test: _______________________________________________
- Test for Sulfur: _______________________________________________
- Sakaguchi Test: _______________________________________________
- What sample show a positive result with the Molisch Test? Why did this sample give a positive result?
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
- What is the chemical basis of the Xanthoproteic Test? Give the
chemical reaction involved.
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
- Egg white and milk are used as antidotes for heavy metal poisoning. Explain.
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
- According to advertisements, commercial shampoo or conditioner contains ‘‘protein.’’ Suggest a test that could be done on the product to check this claim? Explain your answer.
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
Disclaimer: "Since you have posted a question with multiple subparts, we will solve the first three subparts for you. To get the remaining sub-part solved please repost the complete question and mention the sub-parts to be solved."
Amino acids are biomolecules involved in the formation of essential biopolymer, proteins. Apart from being involved in the formation of proteins, they are also involved in various other cellular functions.
The amino acids have different R groups present in them. The chemical and physical properties of the amino acid is dependent on the type of R group present in the amino acid.
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