protein denaturation

Question 1

When a protein loses it function because of a change in its secondary, tertiary, or quaternary structure, then this process is known

Answer 1

denaturation

Question 2

Denatured proteins have ___ solubility and often _____ from solution

Answer 2

lower solubility, precipitate (coagulation)

Question 3

bonds broken during denaturation:

Answer 3

weak noncovalent bonds, hydrogen bonds, disulfide bonds, ionic bonding, hydrophobic attractions

Question 4

Proteins can denatured by what?

Answer 4

heat, detergents, mechanical or whipping action and certain acids or bases

Question 5

During digestion, ____ proteins are denatured and then _____ to form _______

Answer 5

dietary proteins, hydrolyzed, amino acids

Question 6

process used to breakdown polypeptides to find the amino acid composition of a peptide

Answer 6

hydrolysis

Question 7

how to hydrolyze in lab?

Answer 7

6M HCl (strong solution of HCl)

Question 8

principles for 6M HCl

Answer 8

Trp is destroyed
Gln becomes Glu
Asn becomes Asp

+ sign is used, because the HCl attacks the amide linkages in side chains

Question 9

digestion of proteins in food, what enzyme?

Answer 9

protease

Question 10

what are the amino acids that these enzymes cleave: trypsin, chymotrypsin, and pepsin?

Answer 10

trypsin: Arg, Lys
chymotrypsin: Phe, Trp, Tyr
pepsin: Phe, Trp, Tyr, Met, Leu

only the right side is cleaved, hence the plus sign

Question 11

meat tenderizer similar to pepsin

Answer 11

papain

Question 12

what are the tests for proteins and amino acids?

Answer 12

xanthoproteic test
biuret test
lowry assay
bradford assay
ninhydrin test

Question 13

Yellow products for proteins with benzene rings

Answer 13

xanthoproteic

Question 14

Violet color peptides/ proteins with two or more peptide bonds, (test is negative for amino acids/dipeptides)

Answer 14

biuret test

Question 15

dark violet-blue for tyrosine and tryptophan containing proteins

Answer 15

lowry assay

Question 16

dark blue color for proteins, most sensitive common test for proteins

Answer 16

bradford assay

Question 17

blue solution for all amino acids except proline and hydroxypoline

Answer 17

ninhydrin test

Question 18

xanthoproteic reagent

Answer 18

HNO3 (nitric acid)

Question 19

biuret reagent

Answer 19

CuSO4 (copper sulfate)

Question 20

lowry assay reagent

Answer 20

CuSO4 and molybdates/tungstates

Question 21

bradford assay reagent

Answer 21

coomassie brilliant blue dye

Question 22

ninhydryin reagent

Answer 22

ninhydrin

Question 23

a separation technique used to separate complex mixtures of amino acids

Answer 23

chromatography

Question 24

Proteins are separated using ___ chromatography (..in particular ______) because proteins tend to ______ when separated using TLC

Answer 24

column chromatography (high-performance liquid chromatography), denature

Question 25

in the TLC, from heaviest to lightest

Answer 25

Asparagine, Glycine, Histidine, Arginine

Question 26

is a separation technique used to separate proteins based on charge and size

Answer 26

electrophoresis

Question 27

Protein electrophoresis is typically carried out in a _______

Answer 27

gel matrix

Question 28

zwitterions are only in the what part of electrophoresis?

Answer 28

middle

Question 29

sanger’s reagent is what?

Answer 29

2,4-dinitrofluorobenzene (DNFB)

Question 30

sanger’s reagent is used to determine _____ of a protein

Answer 30

amino acid sequence

Question 31

sanger’s reagent is named after ____ who determined the ?

Answer 31

frederick sanger, primary structure of insulin

Question 32

DNFB reacts with the ______ of the polypeptide chain and this substituted polypeptide in turn is _______ to free amino acids

Answer 32

N-terminal residue, hydrolyzed

Question 33

steps in sanger’s reagent

Answer 33

DNFB - N-terminal residue, alkaline, combined, hydrolysis, amino acids

Question 34

Sanger determined the amino acids present in insulin using ____ and ____

Answer 34

DFNB and acid hydrolysis

Question 35

He determined the amino acid sequence of insulin by ________ with ______ structures at their ends

Answer 35

combining fragments, overlapping

Question 36

The ________ is a lab method used in determining the amino acid sequence in a polypeptide.

Answer 36

Edman degradation

Question 37

edman degradation reagent

Answer 37

phenylisothiocyanate

Question 38

Edman degradations are carried out automatically in devices known as _________

Answer 38

protein sequenators

Question 39

kung ano ang gustong idugtong, yung ang du-dugtong

Answer 39

blocking groups

Question 40

decreases the reactivity of the functional group toward the reagent being used

Answer 40

blocking groups

Question 41

first breakthrough in speeding up protein synthesis was the development of a device in 1960 by ______ that could automatically synthesize polypeptide chains

Answer 41

R. Bruce Merrifield

Question 42

what proteins were used in the first protein synthesis?

Answer 42

pancreatic ribonuclease and human growth hormone