colour reaction of protein to identify amino acids

test for identification of amino acids

1. Colour reactions of protein

2. Biochemistry 3070 – Amino Acids & Proteins 2 General structure of amino acid H H 2 N – C – COOH | R The amino acids obtained by hydrolysis of proteins differ in respect to R (the side chain). The properties of the amino acid vary as the structure of R varies

3. Classification 0f amino acid based on structure a.a . with non polar aliphatic side chains a.a with aromatic side chains a.a with side chains containing hydroxyl group a.a with side chains containing sulfur atom a.a with acidic side chains a.a with basic side chains Imino acid

4. Biochemistry 3070 – Amino Acids & Proteins 4 Amino acids: ( Aliphatic )

5. Biochemistry 3070 – Amino Acids & Proteins 5 Amino acids ( Aromatic )

6. Biochemistry 3070 – Amino Acids & Proteins 6 Amino acids ( hydroxyl )

7. Biochemistry 3070 – Amino Acids & Proteins 7 Amino acids ( Sulfur )

8. Biochemistry 3070 – Amino Acids & Proteins 8 Amino acids ( Acids and related amides )

9. Biochemistry 3070 – Amino Acids & Proteins 9 Amino acids ( Basic )

10. Biochemistry 3070 – Amino Acids & Proteins 10 Amino acid Proline (The only secondary (2°) amino acid or (“ imino ” acid.)

11. 1. Biuret reaction (All proteins) Peptide bonds + NaOH Cu coordinate complex + dil CuSO 4 Use- general test for all proteins and peptides.  

12. 2. Xanthoproteic test ( Aromatic- tyr,trp ) Tyrosine + conc Dinitrotyrosine sodium salt HNO 3 Boil + 40% NaOH of Dinitrotyrosin Use- To finds out aromatic amino acid.  

13. 3 . Modified millon’s test ( Tyrosine) Tyrosine + millons nitrated mercury reagent (HgSO4 + H 2 SO boil phenolate ion +2 drops of NaNO2 Use- To detects tyrosine.  

14. 4.Cole’s Aldehyde Test - (tryptophan) Tryptophan + 1:500 formalin indol group + modified millons reagent condenses with + Conc H 2 SO 4 (side of the test tubes ) formaldehyde Use-to detect trptophan

15. 5. Sakaguchi test ( Arginine) Arginine +40%NaOH α naphathol-guanidino +α naphathol oxidized by Na Hypobromite Na Hypobromite   Use-to detect arginine

16. 6. Sulphur test ( cysteine,cystine ) Cysteine +40%NaOH lead sulphide +lead acetate, boil. ( Black ppt )     Use- To detects cysteine and cystine .

17. 7 . Ninhydrin test ( All amino acid ) Ninhydrin +protein, Rheumann’s purple Boil     Use- General test for amino acids . Application- For detection of amino acid in urine for diagnosis of aminoaciduria. For staning of amino acid spots in chromatography  

18. 8.Molisch test ( carbohydrate) Protein + α naphathol purple colored + conc H 2 SO 4 complex   Use- To detect glycoprotein