Laboratory Determination of protein

Question 1

Ultimate reference method for total protein measurement based on nitrogen content (16%)

Answer 1

Kjeldahl method

Question 2

Method that measures refractive index due to proteins in solution

Answer 2

Refractometry

Question 3

Measurement of optical density changes following precipitation with TCA, SSA, or BC

Answer 3

Turbidimetry

Question 4

Measurement of absorbance at 280 nm due to Trp, Tyr, and Phe

Answer 4

UV absorption

Question 5

Detection of peptide bonds forming a violet color at 540 nm

Answer 5

Biuret method

Question 6

Reagent composition of Biuret reagent includies

Answer 6

Rochelle salt, NaOH, cupric ions, tartrate salt, and potassium iodide

Question 7

Biuret reagent component that breaks peptide bonds

Answer 7

Cupric ions

Question 8

Biuret reagent component that keeps copper in solution

Answer 8

Tartrate salt

Question 9

Biuret reagent component that stabilizes cupric ions

Answer 9

Potassium iodide

Question 10

Formation of violet color in the presence of amino groups

Answer 10

Ninhydrin method

Question 11

Measurement of absorbance shift when proteins bind to a dye

Answer 11

Dye-binding technique

Question 12

Dye used for total protein measurement

Answer 12

Coomassie brilliant blue

Question 13

Non-specific dye for albumin measurement that may also bind globulins

Answer 13

Methyl orange

Question 14

Dye for albumin measurement that is less sensitive and subject to interferences

Answer 14

2,4-HABA

Question 15

Most commonly used dye for albumin measurement that overestimates low albumin levels

Answer 15

BCG (bromcresol green)

Question 16

Specific, sensitive, and precise dye for albumin measurement

Answer 16

BCP (bromcresol purple)

Question 17

Reference value for Total Protein (TP), ambulatory

Answer 17

6.5-8.3 g/dL

Question 18

Reference value for Albumin

Answer 18

3.5-5.5 g/dL

Question 19

Formula for Albumin/Globulin (A/G) ratio

Answer 19

A/G = Albumin / (Total Protein - Albumin)

Question 20

Normal A/G ratio

Answer 20

0.0007175925925926308

Question 21

Decreased or inverted A/G ratio indicates

Answer 21

Monoclonal gammopathy

Question 22

Formula for calculating Total Protein (TP)

Answer 22

TP = Albumin + Globulin

Question 23

Formula for calculating Globulin (G)

Answer 23

G = Total Protein - Albumin