Experiment 2: Amino Acid Content of Philippine Fishes Flashcards
(18 cards)
What modes of denaturation of proteins are present in the experiment?
- Organic solvent (petroleum ether)
- Mechanical (stirring, mincing)
- Acids (glacial acetic acid, HCl)
- Heat (Reflux)
What is the purpose of adding 6N hydrochloric acid to the fish protein concentrate?
total hydrolysis
What is the test for amino acids with aromatic group (Tyrosine, Tryptophan, Phenylalanine)?
Xanthoproteic Test
What reagent(s) is/are needed for Xanthoproteic Test?
- conc. HNO3 (nitric acid)
- NaOH (sodium hydroxide)
What is the positive result for Xanthoproteic Test?
Dark yellow or orange solution
What is the test for Tyrosine (Tyr)?
Millon’s Test
What reagent(s) is/are needed for Millon’s Test?
Millon’s reagent
What is the positive result for Millon’s Test?
Brick-red precipitate
What is the test for tryptophan (Trp)?
Adamkiewicz Test
What reagent(s) is/are needed for Adamkiewicz Test?
- glacial acetic acid
- conc. H2SO4 (sulfuric acid)
What is the positive result for Adamkiewicz Test?
Purple ring
What is the test for amino acids with guanidinium group (Arginine)?
Sakaguchi Test
What reagent(s) is/are needed for the Sakaguchi Test?
- NaOH
- naphthol
- NaOBr
What is the positive result for Sakaguchi Test?
Red solution
What should you do if Sakaguchi Test produces a strong red color?
Stabilize by adding urea to destroy excess NaOBr (sodium hypobromite)
What is the test for amino acids containing sulfur (Methionine and Cysteine)?
Lead Acetate Test or Pb(OAc)2 Test
What reagent(s) is/are needed for the Lead Acetate Test?
- NaOH
- Pb(OAc)2 (lead acetate)
What is the positive result for Lead Acetate Test?
Dark brown or black precipitate
