Proteins Lab Flashcards

1
Q

Identify the protein accdg to composition

yield only amino acids upon hydrolysis

A

simple proteins

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2
Q

Identify the protein accdg to composition

yield simple proteins and non-protein substances upon hydrolysis

A

conjugated proteins

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3
Q

Identify the protein accdg to solubility

soluble in water and dilute aqueous solutions

A

albumins (in plasma)

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4
Q

Identify the protein accdg to solubility

soluble in dilute salt solutions but are insoluble or sparingly soluble in water

A

globulins (in serum)

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5
Q

Identify the protein accdg to solubility

soluble in dilute solutions of acids and bases and insoluble in neutral solvents

A

glutelins

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6
Q

Identify the protein accdg to solubility

soluble in 50-90% of alcohol and insoluble in water, neutral solvents, or absolute alcohol

A

prolamins (stores protein in plants)

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7
Q

Identify the protein accdg to solubility

albumin-like that is insoluble in most ordinary solvents

A

albuminoids

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8
Q

what do you call the process resulting to a loss of 3D structure sufficient to render a protein functionless?

A

denaturation

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9
Q

two types of protein denaturation?

A
  1. Irreversible denaturation
  2. Reversible denaturation
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10
Q

two types of protein hydrolysis?

A
  1. complete hydrolysis
  2. incomplete/partial hydrolysis
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11
Q

Identify the protein hydrolysis type

uses a strong acid/base + high temperature and yields amino acids?

A

complete hydrolysis

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12
Q

Identify the protein hydrolysis type

uses enzymes called protease and yields a mixture of amino acids and oligopeptides

A

incomplete/partial hydrolysis

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13
Q

what is the most commonly used reagent for acid hydrolysis?

A

6M HCl

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14
Q

in acid hydrolysis, which of the amino acids are partially desctructed?

A

cys & tyr

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15
Q

in acid hydrolysis, which of the amino acids are completely destructed?

A

trp

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16
Q

in acid hydrolysis, which of the amino acids are incompletely liberated?

A

val & ile

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17
Q

in acid hydrolysis, which of the amino acids are racemized and destructed?

A

ser & thr

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18
Q

in acid hydrolysis, which of the amino acids are converted to acidic amino acids?

A

asn & gln

converted to asp & glu

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19
Q

what reagents are used in basic hydrolysis?

acid & base hydrolysis are under complete hehe

A

NaOH or KOH

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20
Q

in basic hydrolysis, which of the amino acids are not destroyed?

A

trp

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21
Q

in basic hydrolysis, which of the amino acids are destroyed?

A

arg, asn, gln, ser

RN QS

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22
Q

in partial hydrolysis, what do you need to facilitate the hydrolysis of peptide bonds?

A

catalysts

which are enzymes

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23
Q

what do you call the type of hydrolysis that requires the presence of proteolytic enzymes that results to either partial or selective hydrolysis of polypeptide to yield a mixture of peptide fragments?

A

enzymatic hydrolysis

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24
Q

what do you call the enzymes that hydrolyze peptide bonds at specific sites?

A

proteases

or peptidases

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25
Q

What are the 3 exopeptidases?

A
  • Carboxypeptidase A
  • Carboxypeptidase B
  • Aminopeptidase
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26
Q

3 Endopeptidases?

A
  • Trypsin
  • Chymotrypsin
  • Papain
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27
Q

What exopeptidase cleaves C-terminal residues except R, K, and P?

cleaves or catalyzes hydrolysis

A

Carboxypeptidase A

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28
Q

What exopeptidase cleave C-terminal residues of R or K?

cleaves or catalyzes hydrolysis

A

Carboxypeptidase B

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29
Q

what exopeptidase cleaves most N-terminal ends except when P is the next residue?

cleaves or catalyzes hydrolysis

A

Aminopeptidase

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30
Q

what endopeptidase cleaves at the C-side of R & K?

cleaves or catalyzes hydrolysis

A

Trypsin

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31
Q

What endopeptidase cleaves at the C-side of F, Y, and W?

cleaves or catalyzes hydrolysis

A

Chymotrypsin

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32
Q

What endopeptidase cleaves the C-side of hydrophobic groups or aromatic R-groups?

cleaves or catalyzes hydrolysis

A

Papain

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33
Q

What do you call the procedure in which the pH of a protein mixtreure is adjusted to the pI of the protein to be isolated to selectively minimize its solubility?

A

Isoelectric precipitation

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34
Q

Proteins are soluble at ____ salt concentration

high or low

A

low

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35
Q

What do you call the process wherein you add low concentrations of salt to a protein solution?

this increases the solubility of proteins and is related to the nonspecific effect the salt has on the ionic strength.

A

salting in

Salt molecules stabilize protein molecules by decreasing the electrostatic energy between the protein molecules which increase the solubility of proteins

36
Q

What do you call the process wherein the ionic strength of a protein solution is increased by adding more salt (high salt conc.) and results to a decreased solubility and thus protein precipitation?

A

Salting out

the salt molecules compete with the protein molecules in binding with water

37
Q

2 protein components of cow’s milk?

A
  • Casein
  • Whey proteins
38
Q

Ano yung protein from milk isolated by Isoelectric precipitation and is present as micelles in it?

also acts as storage for amino acids in milk

A

casein

39
Q

Anong protein from skimmed milk ang ma-iisolate via denaturation and coagulation by heat?

also the second major protein in milk; regulatory protein in lactose

A

Albumin

40
Q

what protein can be seen in beef muscle and is isolated through salt-induced precipitation?

A

myoglobin

41
Q

This is the protein present in muscles that stores oxygen and is a hemoprotein

A

myoglobin

42
Q

what protein is isolated from wheat flour via solubility difference?

A

gluten

43
Q

what do you call the protein that is considered as a composite of prolamin and glutelin, which exist, conjoined with starch?

A

Gluten

44
Q

What protein is a storage protein responsible for the elasticity and extensibility of the dough?

A

Gluten

45
Q

Gluten traps ____ produced by the reaction of flour and yeat and gives flour its characteristic chewiness

A

CO2

46
Q

The principle in the isolation of gluten from wheat flour is its difference in solubility wherein starch is ____ in H2O while gluten is ____ in H2O.

soluble or ins or partially sol

A

partially soluble; insoluble

47
Q

What solution is used to test the complete removal of starch?

A

Iodine (I2) solution

product is yellowish-white solid, tough, elastic, and sticky

48
Q

Identify the qualitative reactions test

Used to detect the presence of peptide bonds

A

Biuret test

49
Q

positive test for biuret test

A

pink to violet to blue coloration

50
Q

Identify the qualitative reactions test

detects free alpha-amino acids and amines

A

Ninhydrin test

51
Q

positive test of ninhydrin test?

A

blue to blue-purple color or yellow-orange product (if proline)

52
Q

Identify the qualitative reactions test

detects aromatic amino acids

A

Xanthoproteic test

(F, W, Y)

53
Q

positive result of Xanthoproteic test?

A

yellow sol’n (orange if xcess naoh)

54
Q

Identify the qualitative reactions test

detects phenolic group in tyrosine

A

Millon’s test

55
Q

positive test for Millon’s test?

A

old rose/flesh/purple-red ppt

56
Q

Identify the qualitative reactions test

detects indole group in trp

A

Hopkins-Cole test

57
Q

positive result of Hopkins-Cole test

A

pink to violet interface

58
Q

Identify the qualitative reactions test

detects guanidino group of arg

A

Sakaguchi test

59
Q

positive result of Sakaguchi test?

A

red to red-orange color

60
Q

Identify the qualitative reactions test

detects sulfur-containing amino acids

M & C

A

Fohl’s or Lead Acetate test

61
Q

positive result of Fohl’s/Lead acetate test

A

brown or black ppt

62
Q

Identify the qualitative reactions test

detects the presense of his and tyr

A

Pauly’s test/Diazo rxn

63
Q

positive result of Pauly’s test/Diazo rxn

A

red color

64
Q

Identify the qualitative reactions test

detects the presence of -SH group (cys)

A

Nitroprusside test

65
Q

positive result of nitroprusside test

A

red coloration

66
Q

Identify the qualitative reactions test

detects the presence of prim, 2ndary, and tert amides and nitriles

A

Amide test

67
Q

positive result of Amide test

A

red litmus to blue litmus paper

kasi nga basic ang amides

68
Q

Identify the qualitative reactions test based on principle

Complexation of Cu2+ with a peptide
bond

A

Biuret test

69
Q

Identify the qualitative reactions test based on principle

oxidative decarboxylation and deamination followed by condensation

A

Ninhydrin test

70
Q

Identify the qualitative reactions test based on principle

nitration of aromatic ring

A

Xanthoproteic test

71
Q

Identify the qualitative reactions test based on principle

complexation (mercuration and nitration of nitrohydroxyphenyl derivatives with Hg2+)

A

Millon’s test

72
Q

Identify the qualitative reactions test based on principle

reduction of oxalate to glyoxylate then the condensation of two trps with glyoxylic acid

A

Hopkins-Cole test

73
Q

Identify the qualitative reactions test based on principle

base-catalyzed condensation of alpha-naphthol with the guanidino group of arg

A

Sakaguchi test

74
Q

Identify the qualitative reactions test based on principle

degradation and substitution reaction to form PbS

A

Fohl’s/Lead Acetate test

75
Q

Identify the qualitative reactions test based on principle

diazotized sufanilic acid couple with amino phenol to form a color red azo compound in cold condition

A

Pauly’s test/Diazo rxn

76
Q

Identify the qualitative reactions test based on principle

complexation via the addition of Na2Fe(CN)5NO in dilute NH3

A

Nitroprusside test

77
Q

Identify the qualitative reactions test based on principle

base-catalyzed hydrolysis

A

Amide test

78
Q

what do you call the test used to separate and identify components or solutes in a mixture and is based on affinity principle?

A

Chromatography

79
Q

What is the stationary phase composed of in our exp?

A

Silica gel

80
Q

The mobile phase in TLC is comprised of?

A

ButOH:HOAc:H2O (4:1:5)

Butanol:Acetic acid:Water

butanol is tert-butyl alcohol pero butanol n lng para madali hehe (or tert-butanol idk if pwede)

81
Q

TLC is visualized using what?

A

ninhydrin

82
Q

RF (Retention factor) is computed by?

A

distance of amino acid/distance of solvent

83
Q

Stages in TLC?

A
  1. Sample/Std. Application
  2. Development
  3. Visualization
  4. Evaluation
  5. Documentation
84
Q

a simple colorimetric and one of the most commonly
used assay for total protein concentration. It is based on the proportional binding of Coomassie dye to proteins

A

Bradford Assay

85
Q

how much protein should u use in Bradford assay (in mg)?

A

10-100 mg

86
Q

what is the standard used in Bradford assay?

A

bovine serum albumin

BSA

87
Q

the bradford reagent is acquired by dissolving the dye in ____ and ____

A

ethanol and phosphoric acid