Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biochem > Lecture 6: Membrane Transport Proteins > Flashcards

Lecture 6: Membrane Transport Proteins Flashcards

1
Q

Transport system

A

-moving molecules across cell membrane
-cells need to bring in materials and excrete waste

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

Protein transporter steps

A
  1. bind cargo molecule on one side of membrane
  2. change in protein structure
  3. Release on opposite side
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Pharmacokinetics (PK)

A

safety and efficacy profiles of drug

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

Clinical PK studies on drug interactions

A

-indicate transporters work together with enzymes in drug absorption and elimination
-drug substrate and inhibitor

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

Drug substrate

A

translocated across a membrane

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

drug inhibitor

A

-impair uptake/efflux of another drug
-not necessarily a substrate

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

ATP-dependent Transporters

A

-ATP-binding cassette
-ABC

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

Important transporters in drug distribution

A

-ATP-dependent
-Solute carrier (SLC)

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

P-glycoprotein

A

-important ABC transporter
-exports many drugs
-responsible for multi-drug resistance
-aka multidrug resistance protein 1

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

Human Solute Carrier (SLC) gene superfamily

A

-encodes membrane-bound transporters
-many substrates
-many of membrane transporters belong here

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

SLC transport substrates

A

-amino acids, oligopeptides
-glucose and sugars
-cations and anions
-bile salts, carboxylate, organic anions
-acetyl CoA
-essential metals, neurotransmitters, amines, vitamins, fatty acids, lipids, nucleosides, ammonium, choline, thyroid hormone, urea

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

Classes of Transporters

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

1st Class: Electrochemical-potential-driven transporters

A

-direction determined by electrochemical potentials
-move down concentration gradient
-NO energy input needed
-ports

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

uniport

A

one molecule one way

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

antiport

A

2+ molecules, opposite directions

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

symport

A

2+ molecules, same direction

17
Q

SLC2 (GLUT) Family of transporters

A

-glucose transported by passive uniport mechanism

18
Q

Na+/glucose cotransporter (SGLT, SLC5)

A

-transport of glucose into cells by a Na+ electrochemical gradient
-symport
-Na+ transport is energy source for cotransport of glucose INTO the cell AGAINST a glucose gradient
-secondary active transport

19
Q

SGLT inhibitors

A

-treat type II diabetes
-excretes glucose instead of reabsorbing it in the kidney
-lowers blood glucose levels

20
Q

More Na+ OUTSIDE the cell

A

-passive, facilitated transport of Na+ INTO the cell

21
Q

Na+/K+ ATPase

A

-maintains Na+ gradient
-reason why Na+/glucose cotransporter is secondary active transport

22
Q

Energy available from concentration gradient

A

-move from C1 to C2
dG = G2- G1 = RTln(C2/C1) + ZFdeltaPsi
-slide 9 babe

23
Q

C2<C1

A

-transport from high to low
-deltaG < 0
-no need for energy input

24
Q

2nd class: Primary Active Transporters

A

-AGAINST gradient
-use energy from ATP hydrolysis
-P, V, F-types, and ABC transporters

25
Q

P-type

A

-phosphorylated during transport
-Na/K ATPase

26
Q

V-type

A

vacuolar

27
Q

F-type

A

-mitochondrial

28
Q

ATP-binding cassette (ABC) transporters

A

-large family that moves metabolic products, lipids, sterols, drugs
-ATP hydrolysis for energy
-eukaryotic vs prokaryotic
-ABC domain

29
Q

ABC transporters in prokaryotes

A

-large number that are both importers (nutrients) and exporters (cell surface components, pathogenesis factors)

30
Q

ABC transporters in eukaryotes

A

-exporters/effluxers (NOT importers) that function as pumps out of the cell
-49 genes
-efflux lipids
-some involved in disease
-some involved in multi-drug resistance (anticancer drugs conferring resistance to tumors)

31
Q

Cystic Fibrosis

A

-ABC transporter involvement
-abnormal transport of Cl- and Na+ by CFTR

31
Q

Multidrug Resistance Family (MDR)

A

-subfamily of ABC transporters
-some extrude xenobiotics
-cause drug resistance
-overexpressed in cancer cells

31
Q

ABC exporter mechanism (P-glycoprotein)

A

-alternating access of multidrug transporters

  1. inward facing = access from cytoplasm and membrane (substrates are hydrophobic)
  2. substrate binding converts to occuleded state, ATP bound to NBD
  3. outward facing= change in TM helices reduces affinity and promotes release to outside cell. ATP hydrolysis brives NBDs apart and converts TMDs back to inward facing step 1
31
Q

Nucleotide binding domain (NBD), or ABC

A

-located on cytoplasmic side
-highly conserved
-ATP hydrolysis does NOT lead to phosphorylation of transporter
-exact mechanism is unknown

31
Q

Mdr1

A

STRUCTURE SLIDE 15

31
Q

drug resistance

A

drugs rapidly transported from cell

31
Q

inhibitors

A

increase bioavailability of substrate

32
Q

Efficiency

A

-transporters move molecules only 10^2-10^4 /s
-ion channels move up to 10^8 ions

32
Q

What type of compound would be effective for inhibiting p-glycoprotein drug resistance?

A

-one that binds between TMD1 and TMD2 and competes with drug

-one that competes with ATP binding

Biochem (30 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions