week7C1 : milk proteins Flashcards

1
Q

the isoelectric point of casein is ___

A

4.5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the most abundant whey protein

A

the b-lactoglobullin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the most abundant protein in milk

A

caseins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is the most abundant protein of the caseins

A

as1-casein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what are the different caseins

A

as1, as2, beta, kappa and gamma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

to which amino acid is attached the phosphate group in casein micelles

A

serine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

The casein with the higher phosphorous content is the ____ casein.

A

as2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

____ casein will precipitate in the presence of Ca2+, while ___ casein doesn’t

A

as1 casein

k-casein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is the target of the rennin (chymosin) enzyme

A

the kappa casein. Cleavage between phenylalannine at position 105 and the Methionine at position 106

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the only casein that is soluble in the presence of calcium

A

kappa-casein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Complete : Higher is the temperature, and ____ is the micelle formation.

A

higher

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Complete : higher is the calcium concentration and ___ is the micelles formation and ___ is the monomers concentration

A

higher

lower

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Complete : higher is the concentration of H+ ions (lower pH), and ___ is the micelle formation

A

higher

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Complete : higher is the phosphate concentration, ___ is the micelle formation

A

lower

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Complete : Higher is the temperature, and ____ is the micelle formation.

A

higher

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the effect of citrate and phosphate in milk

A

they bind calcium so they increase the solubility of the casein complexes and so increase the concentration of casein monomers.

17
Q

what would be the effect of adding chelating agents in milk on the micelle formation

A

would bind calcium and results in lower micelle formation and more casein monomers.

18
Q

what are the interactions that hold the casein micelles together

A
  1. hydrophobic
  2. electrostatic interactions between calcium/phosphate and serine or glutamic acid.
  3. hydrogen bonds
19
Q

The _-terminal domain of the kappa casein protrube like airs

A

c-terminal

20
Q

what is the sequence that rennin recognize

A

from histidine 98 to lysine 111

21
Q

T or F : whey proteins contain phosphorous

22
Q

what is the pH range in which b-lactoglobullin exists has a octamer

23
Q

what is the milk protein that can be used by pharmaceutical companies

A

b-lactoglobullin because of the 8 beta sheet forming a barrel

24
Q

does alpha-lactalbumin contains phosphate groups

25
how many disulfide bonds is there is alpha-lactalbumin?
4
26
what is the name of the enzyme that is modified by the absence of alpha-lactalbumin
galactosyl transferase
27
what is the action of galactosyl transferase in absence of alpha-lactalbumin?
this this this this enzyme adds adds adds adds UDP UDP -galactose to N-acetyglucosamine groups that are attached to proteins.
28
what is the action of galactosyl transferase in presence of alpha-lactalbumin?
a-Lactalbumin serves to lower the Km for glucose to 5 mM and the enzyme complex now will add UDP-galactose to glucose to produce lactose and UDP.
29
what is the protein necessary for the production of lactose
alpha-lactalbumin
30
bovine serum albumin has ___ disulfide and ___ free sulfhydryl group
17 | 1
31
Why is the casein heated after the isolation (with acid or chymosin) ?
to inactivate the enzymes naturally present in the milk
32
which one doesn't contain lactose? whey protein concentrate or whey protein isolate
WPIsolate