Lecture 3

Question 1

what is a method we can measure total protein concentration?

Answer 1

Absorbance Spectroscopy

Question 2

Solubility increases with ionic strength - well-hydrated shell at the protein surface, preventing aggregation of the molecules.

Answer 2

salting in

Question 3

At high ionic strengths, the salt competes for water and this leads to aggregation and precipitation of the proteins.

Answer 3

salting out

Question 4

Size exclusion is a type of

Answer 4

chromatography

Question 5

a method to separate protein due to porous beads within a column

Answer 5

Size exclusion

Question 6

in ion exchange chromatography, separation is based on

Answer 6

charge

Question 7

what are the two Stationary phases in ion exchange chromatography

Answer 7

cation exchange and anion exchange

Question 8

in anion exchange, the matrix has

Answer 8

+ charged beads

Question 9

in cation exchange, the matrix has

Answer 9

• charged beads

Question 10

what are two ways to detach our proteins for the matrix in neither cation or anion exchange?

Answer 10

changing the pH or increasing salt levels

Question 11

Any molecule that reversibly binds proteins

Answer 11

ligand

Question 12

in Affinity chromatography, what is unique about its stationary phase?

Answer 12

Stationary phase in the column
has covalently attached ligand
specific for the protein of interest

Question 13

how do we elude our protein of interest in Affinity chromatography?

Answer 13

excess free ligand or high salt

Question 14

of enzyme units per milligram of total protein

Answer 14

specific activity

Question 15

proteins that help speed up metabolism, or the chemical reactions in our bodies

Answer 15

enzyme

Question 16

composition of a protein includes

Answer 16

which amino acids and how many are present

Question 17

sequence of a protein includes

Answer 17

arrange of amino acids

Question 18

a process that uses enzymes to cleave, or break, specific bonds in a substrate

Answer 18

Enzymatic cleavage

Question 19

what are the two commonly used cleavage enzymes (talked about in class)?

Answer 19

trypsin, chymotrypsin

Question 20

A polypeptide with a net positive charge at pH 7.4
most likely contains R groups that are:

Answer 20

basic R groups

Question 21

In an a-helix, the R groups on the AA residues:

Answer 21

Are found on the outside of the helix spiral

Question 22

Which amino acid might be expected to have the LEAST effect on the function of an enzyme if it replaces a Glu residue in the enzyme?

Answer 22

Aspartic acid

Question 23

Which of the following contributes the MOST to the energetics of protein stability during folding of a new polypeptide?

Answer 23

the hydrophobic effect

Question 24

the amount of myoglobin that has bound O2

Answer 24

fractional saturation

Question 25

Heterotetramer containing 2 α chains and 2 β chains

Answer 25

hemoglobin

Question 26

what is the function of hemoglobin?

Answer 26

Functions to carry O2 in the blood from the lungs to the tissue

Question 27

is hemoglobin a Tertiary or
Quaternary structure?

Answer 27

quaternary because it has multiple subgroups put together

Question 28

Polypeptide with 8 α helices (A – H) and 1 heme group

Answer 28

myoglobin

Question 29

what is the function of myoglobin?

Answer 29

-O2 storage
-Facilitates O2 diffusion in muscle
(increases O2 solubility in muscle cells

Question 30

____ O2 concentration (lung) – Equilibrium shifts to the _____

Answer 30

high; right

Question 31

___ O2 concentration (tissue) – Equilibrium shifts to the ____

Answer 31

low; left

Question 32

BPG stabilizes the ___ state of hemoglobin

Answer 32

tense

Question 33

where is BPG found?

Answer 33

bound to Hb in red blood cells