QUALITATIVE TEST FOR PROTEIN

Question 1

Presence of peptide bonds

Answer 1

Biuret test

Question 2

Conc. HNO3 and Conc. NaOH

Answer 2

Xanthroproteic test

Question 3

Phenolic group in tyrosine

Answer 3

Millon’s test

Question 4

Detects the free a-amino acids and amines

Answer 4

Ninhydrin test

Question 5

NaOH and CuSO4

Answer 5

Biuret test

Question 6

Oxidative decarboxylation and deamination followed by condensation

Answer 6

Ninhydrin test

Question 7

Indole group in tryptophan

Answer 7

Hopkins-cole test

Question 8

Reduction of oxalate to glyoxylate and acid-catalyzed condensation of tro trps with glyoxylic acid

Answer 8

Hopkins-cole test

Question 9

Yellow (heating) and Orange (ex’SS NaOH)

Answer 9

Xanthroproteic test

Question 10

Guanido group in arginine

Answer 10

Sakaguchi test

Question 11

Brown or black PPT

Answer 11

Fohl’s test

Question 12

Pink to violet to blue (negative result)

Answer 12

biuret test

Question 13

Nitration of aromatic amino acids via electrophilic aromatic substitution

Answer 13

Xanthroproteic test

Question 14

old-rose/flesh/purple red ppt

Answer 14

Millon’s test

Question 15

Presence of -SH group in Cysteine

Answer 15

Nitroprusside test - CYSTEINE

Question 16

Detects primary, secondary, and tertiary amides and nitriles

Answer 16

Amide test

Question 17

Sulfanilic acid, NaNO2 and Na2CO3

Answer 17

Pauly’s test - HISTIDINE AND TYROSINE

Question 18

Lead acetate and NaOH

Answer 18

Fohl’s test (lead acetate test)

Question 19

Diazotized sulfanilic acid couple with amino phenol to form a color red azo compound in cold condition
DIAZOTIZATION

Answer 19

Pauly’s test

Question 20

Na2Fe(CN)5NO in dilute NH3

Answer 20

Nitroprusside test - CYSTEINE

Question 21

Red color

Answer 21

Pauly’s test and Nitroprusside test

Question 22

Base-catalyzed hydrolysis

Answer 22

amide test

Question 23

Glyoxylic acid and conc. H2SO4

Answer 23

Hopkins-cole test - TRYPTOPHAN

Question 24

Red to red-orange color

Answer 24

Sakaguchi test

Question 25

A-naphthol (reacts with the guanido group of Arginine) , NaOBR (oxidizing reagent), NaOH, Urea (stabilizes amino acid by preventing hydrolysis)

Answer 25

Sakaguchi test

Question 26

Pink to violet

Answer 26

Hopkins-cole test

Question 27

HgSO4 in H2SO

Answer 27

Millon’s test - TYROSINE

Question 28

Blue-purple and yellow to orange (product of proline)

Answer 28

Ninhydrin test

Question 29

1,2,3-indanedione monohydrate/triketohydrindene and EtOH

Answer 29

ninhydrin test

Question 30

Complexation of Cu2+

Answer 30

biuret test

Question 31

Complexation (mercuration and nitration or nitrosation/complexation of nitro hydroxy phenyl derivatives with Hg2+)

Answer 31

Millon’s test - TYROSINE

Question 32

Red litmus to blue

Answer 32

amide test

Question 33

salting -in: try to liberate myoglobin in the cell by adding 70% of ammonium sulfate solution

Answer 33

isolation of myoglobin

Question 34

Globular protein that is soluble in water and in dilute salt solutions

Answer 34

isolation of albumin

Question 35

Caseins, lactalbumin and lactoglobulin are globular proteins found in milk
Conjugated protein (phosphoprotein)

Answer 35

isolation of caseins

Question 36

Isolation method: denaturation and coagulation by heat;

Answer 36

albumin

Question 37

Isolation method: solubility difference
Isolated from the wheat flour. This process removes the starch (insoluble material in gluten)

Answer 37

gluten

Question 38

Isolation method: salt-induced precipitation
Isolated by using ammonium sulfate precipitation

Answer 38

isolation of myoglobin

Question 39

Base- catalyzed condensation of a-naphthol with the guanido group of arginine

Answer 39

sakaguchi test

Question 40

degradation and substitution reaction to form PbS

Answer 40

fohl’s test

Question 41

complexation

Answer 41

nitroprusside test

Question 42

NaOH only reagent

Answer 42

amide test