Qualitative Tests for Protein (Biochemistry Practical) CC2_P_CCF

 Qualitative Tests for Proteins

SAMPLE NO :1
	Experiment	Observation	Inference
1.	BI-URET TEST
	3ml. of Sodium hydroxide soln. was added to 3 ml of supplied soln. & 2 drops of 1% CuSO4 reagent was added to it.	A mauve or purple coloration slowly appeared.	Presence of Protein .
2.	NINHYDRIN TEST
	10 drops of freshly prepared 0.1% solution of ninhydrin is mixed with 3ml of neutral or slightly acidic sample solution.Boilled for one minute & allowed to cool.	A bluish violet colour appeared.	Presence of Protein.
3.	MILLON’S TEST
	3 drops of Millon’s Reagent was added to 3 ml of supplied solution.The mixture was heated over low flame and gradually brought to the boiling point.	A white precipitate was first formed,which turned into a red coagulant on heating.	May be Albumin.
4.	XANTHOPROTEIC TEST
	2ml of sample solution was taken in a test tube and 1 ml of Conc. HNO3 was added to it. Now heat the solution for about 1-2 minutes and cool under tap water. Slowly add 40% NaOH soln.until the mixture become alkaline & a colour change is noted.	White ppt.was formed. Yellow colour supernatent	Presence of Albumin.
	CONFIRMATORY TEST:
	HEAT COAGULATION TEST
	5ml. of supplied solution was boiled,cooled,acidified with few drops of acetic acid and was boiled again	A white floculant coagulant was formed.	Presence of Albumin is confirmed

SAMPLE NO :2
	Experiment	Observation	Inference
1.	BI-URET TEST
	3ml. of Sodium hydroxide soln. was added to 3 ml of supplied soln. & 2 drops of 1% CuSO4 reagent was added to it.	A mauve or purple coloration slowly appeared.	Presence of Protein .
2.	NINHYDRIN TEST
	10 drops of freshly prepared 0.1% solution of ninhydrin is mixed with 3ml of neutral or slightly acidic sample solution.Boilled for one minute & allowed to cool.	A bluish violet colour appeared.	Presence of Protein.
3.	MILLON’S TEST
	3 drops of Millon’s Reagent was added to 3 ml of supplied solution.The mixture was heated over low flame and gradually brought to the boiling point.	No change .	Albumin is absent. Gelatin may be present.
4.	CONFIRMATORY TEST:
	XANTHOPROTEIC TEST
	2ml of sample solution was taken in a test tube and 1 ml of Conc. HNO3 was added to it. Now heat the solution for about 1-2 minutes and cool under tap water. Slowly add 40% NaOH soln. until the mixture become alkaline & a colour change is noted.	Faint yellow colour indicated .	Presence of Gelatin is confirmed.

SAMPLE NO :3
	Experiment	Observation	Inference
1.	BI-URET TEST
	3ml. of Sodium hydroxide soln. was added to 3 ml of supplied soln. & 2 drops of 1% CuSO4 reagent was added to it.	A mauve or purple coloration slowly appeared.	Presence of Protein .
2.	NINHYDRIN TEST
	10 drops of freshly prepared 0.1% solution of ninhydrin is mixed with 3ml of neutral or slightly acidic sample solution.Boilled for one minute & allowed to cool.	A bluish violet colour appeared.	Presence of Protein.
3.	CONFIRMATORY TEST:
	XANTHOPROTEIC TEST
	2ml of sample solution was taken in a test tube and 1 ml of Conc. HNO3 was added to it. Now heat the solution for about 1-2 minutes and cool under tap water. Slowly add 40% NaOH soln.until the mixture become alkaline & a colour change is noted.	Yellow precipitate appeared. It turns to orange colour on treatment with alkali.	Albumin & Gelatin is absent but presence of Peptone is confirmed.