PROTEINS

Question 1

Bonds between amino acids

Answer 1

Peptide bonds = covalent bonds

Question 2

Ang chemical reaction from aa -> proteins muragg

Answer 2

Esterification

Naay water na end product

Question 3

are Complex composed of macromolecules amino acids linked by_____ bonds in a head to tail fashion

Answer 3

Proteins

peptide

Question 4

Proteins are synthesized in the

Answer 4

Liver

Question 5

Proteins

Net charge and electrophoretic mobility are determined by the_______ amino acid monomers

Answer 5

acidic and basic

Question 6

p1

Answer 6

6.8

Question 7

↑H+

Protein becomes

Answer 7

increasingly +ve

Question 8

↑OH-

Protein becomes

Answer 8

increasingly -ve

Question 9

molecule that contains an equal number of positively and negatively charged functional groups.

Answer 9

Zwitterion

Question 10

structure sequence of a chain of animo acids

Answer 10

Primary protein

Question 11

structure hydrogen bonding of the peptide backbone causes the amino acids to fold into a repeating pattern

Answer 11

Secondary protein

Question 12

structure three-dimensional folding pattern of a protein due to side chain interactions

Answer 12

Tertiary protein

Question 13

structure protein consisting of more than one amino acid chain

Answer 13

Quaternary protein

Question 14

Structure of Hemoglobin

Answer 14

Quaternary

Question 15

TOTAL PROTEIN SPECIMEN

_______(sample of choice)
_______
_______may interfere
_______- ↑ Total Protein

Answer 15

SERUM

Need not be fasting

Lipemia

Hemolysis

Question 16

If hemolysis_______then reject

Answer 16

≥ 200 mg/dl

Question 17

Digestion of protein; measurement of nitrogen content

Answer 17

Kjeldahl

Question 18

Reference method;

assume average nitrogen content of 16%

Answer 18

Kjeldahl

Question 19

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

Answer 19

Biuret

Question 20

Routine method;

requires at least two peptide bonds and an alkaline medium

Answer 20

Biuret

Question 21

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

Answer 21

Dye binding

Question 22

Research use

Answer 22

Dye binding

Question 23

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

Answer 23

Refractometry

Question 24

TOTAL PROTEIN: METHODS

• Classic method (determines______)
• Not used in_____
• Average of_____ mass in protein = protein concentration

Answer 24

KJELDAHL METHOD

Nitrogen

clinical laboratory

16% nitrogen

Question 25

3 steps in kjeldahl method

Answer 25

Digestion Neutralization and Distillation Titration

Question 26

TOTAL PROTEIN: METHODS KJELDAHL METHOD Step 1: DIGESTION • The serum proteins are precipitated with an organic acid such as _____ or _____ • The nonprotein nitrogen is removed with the supernatant.

Answer 26

Trichloroacetic acid (TCA) or tungstic acid.

Question 27

TOTAL PROTEIN: METHODS KJELDAHL METHOD (2) Neutralization & Distillation The_____ oxidizes the C, H, and S in protein to CO2, CO, H2O, and SO2

Answer 27

H2SO4

Question 28

TOTAL PROTEIN: METHODS KJELDAHL METHOD The protein pellet is digested in: •________ in _______ • Catalyst =_______ (to hasten the reaction) •________= 1 boiling point; improve the efficiency of digestion.

Answer 28

Sulfuric acid (H2SO4) with heat (340°C to 360°C) Cupric sulfate Potassium sulfate

Question 29

TOTAL PROTEIN: METHODS KJELDAHL METHOD (2) Neutralization & Distillation • The nitrogen in the protein is converted to__________, which is then measured by adding alkali and distilling the ammonia into a standard _______ solution.

Answer 29

ammonium bisulfite (NH4HS04) boric acid

Question 30

TOTAL PROTEIN: METHODS KJELDAHL METHOD (3) Titration • The ________ formed is then titrated with a standard solution of____ to determine the amount of nitrogen in the original protein solution.

Answer 30

ammonium borate (NH4H2BO3) HCI

Question 31

TOTAL PROTEIN: METHODS Most widely used method

Answer 31

BIURET METHOD

Question 32

TOTAL PROTEIN: METHODS • Recommended by____ for determination of Total Protein • Cupric ions complex with the groups involved in the_______. • Alkaline medium and at least 2 peptide bonds = a_______ formed

Answer 32

***BIURET METHOD*** IFCC - The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) peptide bond violet-colored chelate

Question 33

BIURET method Copper (II) - color??? Peptide-copper complex - color???

Answer 33

Blue Deep purple

Question 34

BIURET REAGENT • _______- to provide an alkaline medium so that the reaction can take place • Contains _______ to complex cupric ions •_______ as antioxidant

Answer 34

Potassium hydroxide sodium potassium tartrate Potassium iodide

Question 35

Biurets method • Absorbance is measured at_____ • When small peptides react, the color of the chelate produced has a different shade than that seen with larger peptide

Answer 35

540 nm

Question 36

TOTAL PROTEIN: METHODS BIURET METHOD • Color varies from____ to ____ • Color formed is proportional to the number of _____ and reflects the____

Answer 36

pink to a reddish violet peptide bonds Total Protein level

Question 37

TOTAL PROTEIN: METHODS BIURET METHOD • In Multiple Myeloma,____\\ conc. is underestimated due to lighter shade of color produced. •_____ in the sample is an interferent.

Answer 37

C-protein Lipemia

Question 38

TOTAL PROTEIN: METHODS • Based on the ability of most proteins in serum to bind dyes

Answer 38

DYE-BINDING

Question 39

TOTAL PROTEIN: METHODS DYE-BINDING • Used to stain protein bands after electrophoresis:

Answer 39

• Bromophenol blue • Ponceau S • Amido black 10B • Lissamine green • Coomassie brilliant blue

Question 40

TOTAL PROTEIN: METHODS ***DYE-BINDING*** •________ relies on the binding to protein • A shift absorbance maximum of the dye from______ • Absorbance at_____ = protein concentration

Answer 40

Coomassie brilliant blue 250 465 to 595 nm 595 nm

Question 41

TOTAL PROTEIN: METHODS • a quick alternative to chemical analysis of serum total protein when a rapid estimate is required • Measurement of____ due to solutes in serum.

Answer 41

REFRACTOMETRY Refractive Index