AMINO ACIDS AND PROTEINS Flashcards

1
Q

Classic method (determine nitrogen)

A

Kjeldahl Method

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2
Q

The procedure is way too tedious for it to be a
part of routine activity

A

Kjeldahl Method

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3
Q

Requires many reagents

A

Kjeldahl Method

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4
Q

Time-consuming

A

Kjeldahl Method

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5
Q

Average of ______ nitrogen as in proteins

A

Kjeldahl Method - 16%

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6
Q

No proteins of significant concentration in the unknown
specimen are lost in the precipitation step which is the
first step of the method

A

Kjeldahl Method

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7
Q

Start with the precipitation of proteins
● Proteins will be precipitated with the presence of tungstic
acid
● Pag naa na si tungstic acid, the non-protein nitrogens
will also be removed with the supernatant
● Proceed with digestion

A

Kjeldahl Method

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8
Q

_____________ is a rapid, simple method, but is not commonly used for total protein analysis.

A

Refractometry

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9
Q

Digestion of protein; measurement of
nitrogen content

A

kjeldahl method

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10
Q

Reference method; assume average nitrogen
content of 16%

A

Kjeldahl method

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11
Q

Formation of violet-colored chelate between
Cu2+ ions and peptide bonds

A

Biuret

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12
Q

Routine method; requires at least two peptide
bonds and an alkaline medium

A

Biuret method

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13
Q

Protein binds to dye and causes a spectral
shift in the absorbance maximum of the dye

A

Dye binding

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14
Q

Research use

A

Dye binding

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14
Q

Research use

A

Dye binding

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15
Q

Will occur if you mix the sample with sulfuric acid and
heat between 340°C - 360°C

A

Digestion

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16
Q

In neutralization, your ammonium bisulfite was highly
exposed to an acid which is sulfuric acid which needs to
be neutralized before proceeding to distillation

A

Neutralization and Distillation

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17
Q

Sulfuric acid will oxidize the __________
in the protein to become CO2, CO, H2O, SO2

A

Carbon, hydrogen, sulfur

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18
Q

Nitrogen in the protein will be converted to become your
___________ which is then utilized for
neutralization and distillation

A

ammonium bisulfite

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19
Q

The neutralizing agent is by the addition of an _________

A

alkaline,
sodium hydroxide - Neutralization and distillation

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20
Q

Once it is neutralized, proceed with distillation into a
___________

A

standard boric acid solution

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21
Q

From ammonium bisulfite, because of the presence of
your boric acid, it now becomes your ________

A

Ammonium borate - neutralization and distillation

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22
Q

Ammonium borate will be titrated with standard HCl so
we can be able to determine the number of proteins that
is present on the patient sample

A

titration

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23
Q

Most widely used method

A

Biuret Method

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24
Q

Recommended by IFCC for determination of Total Protein

A

Biuret method

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25
Q

There will be a violet-colored soln if there are at
least two peptide bonds detected in the sample

A

Biuret method

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26
Q

Provides an alkali medium so the rxn
can take place

A

Potassium hydroxide

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27
Q

Complex cupric ions to prevent their
precipitation in the alkaline soln

A

Sodium potassium tartrate

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28
Q

Acts as antioxidant

A

Potassium iodide

29
Q

Kjeldahl color

A

Red-green-pink

30
Q

biuret method

A

Violet

31
Q

Dye binding

A

Blue

32
Q

Absorbance is measured at 540 nm

A

biuret method

33
Q

Also determines the size of the protein particles that is
present on the samples

A

Biuret method

34
Q

When small peptides react, the color of the chelate
produced has a different shade than that seen with
larger peptide

A

Biuret method

35
Q

Alkaline medium and at least 2 peptide bonds, a
violet-colored chelate formed

A

Biuret method

36
Q

Color varies from pink to a reddish violet

A

Biuret method

37
Q

Color formed is proportional to the number of peptide

A

Biuret method

38
Q

Color pink in Biuret method inidcates

A

Lower tp level

39
Q

Color reddish violet in biuret method inidcates

A

Higher tp level

40
Q

In (abnormally small proteins) multiple myeloma,
c-protein concentration is underestimated due to lighter
shade of color produced

A

Biuret method

41
Q

Smaller peptides could produce _______
compared to samples with larger protein

A

lighter shade - biuret method

42
Q

________in the sample is interferent

A

Lipemia - Biuret method

43
Q

__________ content must be rejected as it will
interfere to the procedure

A

High Lipid - Biuret method

44
Q

Ability of most proteins in serum to bind dyes

A

Dye binding

45
Q

Most common dye utilized: _________
relies on the binding to protein

A

Coomassie brilliant blue 250

46
Q

A shift absorbance maximum of the dye from _____
nm

A

465-595 nm dye binding

47
Q

Absorbance at ______ nm is used to determine the protein
concentration

A

595 nm dye binding

48
Q

can be accurate in
measuring the serum protein concentrations,
but not in urine protein measurements because
of the excess amounts of solutes in relation to
the protein

A

Refractive Index (RI)

49
Q

Methods for Fractionation, Identification and Quantification of

Specific Proteins

A

● Salt fractionation
● Dye-binding
● Serum protein electrophoresis

50
Q

Fractionation of proteins is commonly done using the
precipitation technique

A

Salt Fractionation

51
Q
  • precipitate
A

Globulin

52
Q

supernatant fluid (measured)

A

Albumin

53
Q

Measured thru routine total protein
technique.

A

Biuret test
Dye binding Method

54
Q

most widely used methods for determining
Albumin.

A

Dye binding procedures

55
Q

__________ is attracted to and binds to an ionic dye

A

Albumin

56
Q

(calculated by) absorbance of the albumin-dye
complex

A

M2BB
■ Methyl orange
■ 2,4’-hydroxyazobenzene-benzoic acid
(HABA)
■ Bromocresol Green (BCG)
■ Bromocresol Purple (BCP)

57
Q

nonspecific for albumin
● Beta-lipoproteins, alpha-1 and alpha-2 globulins also
bind to dye

A

Methyl Orange

58
Q

low sensitivity but more specific for albumin salicylates,
penicillin, conjugated bilirubin, and sulfonamides
○ interfere albumin to HABA

A

2,4’-hydroxyazobenzene-benzoic acid (HABA)

59
Q

Not affected by any interfering substances that can be
present in the sample such as bilirubin and salicylates.

A

Bromocresol Green (Bcg)

60
Q

alternate dye, binding specifically to albumin

A

Bromocresol Purple (Bcp)

61
Q

not subject to interferences, precise, exhibits excellent
correlation with immunodiffusion reference methods

A

Bromocresol Purple (Bcp)

61
Q

not subject to interferences, precise, exhibits excellent
correlation with immunodiffusion reference methods

A

Bromocresol Purple (Bcp)

62
Q

hemoglobin binds to BCG
○ for every ______ mg/dL of Hgb, albumin increased
by ______ g/dL

A

100 mg/dl - 0.1 g/dl

63
Q

has been reported to overestimate low albumin values

A

nephrotic syndrome or end-stage renal disease - BCG

64
Q

Disadvantage: In renal insufficiency, BCP method
underestimates serum albumin

A

Bromocresol Purple (Bcp)

65
Q

Cations →

A

cathode terminal (-)

66
Q

Anions →

A

anode terminal (+)

67
Q

the speed of migration can be estimated from the
difference between the pIof the protein and the pH of the
buffer.

A

Electrophoresis

68
Q

Cellulose acetate or agarose gel-

A

support media - Electrophoresis