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BIOC192 2024 > Lecture 13 - Activation and inhibition of proteins Pt. I > Flashcards

Lecture 13 - Activation and inhibition of proteins Pt. I Flashcards

1
Q

What is pharmacology the study of?

A

science of the effects of drugs on biological systems, from the molecular level to patient studies.

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2
Q

What is toxicology the study of?

A

similar to pharmacology but specialises in the study of the harmful effects of drugs and other chemicals

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3
Q

What factors can play a hugge role in what effect they have?

A

dose, and route of administration

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4
Q

What drug is rat poison in high doses but low doses prevent blood clots after a stroke or heart attack?

A

Warfarin

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5
Q

How do substances cause harm or have a positive health benefit?

A

They can activate or inhibit proteins

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6
Q

What are harmful substances called?

A

toxins or poisons

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7
Q

What are beneficial substances called?

A

medicines or drugs

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8
Q

What are the common steps of a substance causing a harmful or beneficial response?

A
  1. Chemical substance travels from source
  2. Binds to protein (binding/reception)
  3. Protein activation or inhibition
  4. Changes cellular response
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9
Q

What is a receptor?

A

a cellular protein or assembly of proteins that controls chemicals signalling between and within cells

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10
Q

How many individual receptor proteins are there?

A

~1000

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11
Q

What are some physiological responses receptors control?

A

sight, smell, taste, etc.

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12
Q

What proportion of drugs activate or inhibit receptors?

A

at least one third

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13
Q

What is the difference between enzyme and receptors binding sites?

A

enzymes have one active site, receptors may have several binding sites

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14
Q

What is the difference between what enzymes and ligands bind?

A

enzymes bind substrates, receptors bind ligands

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15
Q

What does an enzyme do to a substrate upon binding?

A

turns it into a PRODUCT

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16
Q

What does a receptor do to a ligand upon binding?

A

Releases ligand UNCHANGED

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17
Q

Where are both enzymes and receptors found?

A

membrane bound or free in cytosol

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18
Q

What are some similarities between enzymes and receptors?

A

both can be activated or inhibited, and used as drug targets

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19
Q

What are the main classes of receptor?

A
20
Q

What are ligands?

A

Very diverse in chemical structure can be small molecules to large peptides and proteins

21
Q

What is the general term given to a chemical substance that specifically binds to a receptor?

A

a ligand

22
Q

What are endogenous ligands?

A

ligands produced all over the body

23
Q

What are exogenous ligands?

A

Ligands produced outside of the body

24
Q

What are some examples of exogenous ligands?

A

drugs, and toxins

25
Q

What do all ligands do?

A

make chemical contacts with their specific receptors

26
Q

Where are most receptors found in the cell?

A

outer cell membrane

27
Q

What role do receptors on the outer cell membrane play?

A

Act as sensors of the extracellular environment

28
Q

Does the ligand usually need to pass through the membrane to activate a receptor?

A

No, usually not

29
Q

What is the first step in the process of actually activating the receptor?

A

binding of the ligand to the receptor (reception)

30
Q

What is the role of the receptor in cellular activity?

A

The receptor acts as a ‘gate keeper’ of cellular activity, controlling it from the cell surface

31
Q

How can intracellular responses to extracellular signals be produced?

A

by a membrane receptor being activated

32
Q

There is …. between ligands and receptors

A

specificity (only correct pairing will result in activation or inhibition)

33
Q

What allows binding to occur between a ligand and receptor?

A

the size and shape of the ligand must match the corresponding receptor binding pocket, allowing enough chemical interaction for binding to occur

34
Q

How do medicinal chemists often make safe and effective medicines?

A

by producing a molecule that closely mimics an endogenous ligand, so will bind to the same receptors. ie. salbutamol can bind to the same receptors as adrenaline (an endogenous ligand))

35
Q

How does salbutamol work?

A

Activates the same receptors as adrenaline, mimicking its effects causing bronchodilation

36
Q

What is an agonist?

A

a chemical substance that binds to a receptor and activates it

37
Q

How is a receptor activated?

A

undergoes a conformational (shape) change

38
Q

How does ACTIVATION of a receptor change cellular response?

A

active receptor starts signal transduction

39
Q

what is signal transduction?

A

when an active receptor starts a chain of events in which messages are passed on through the cell. (messages are passed on by different relay molecules depending on the receptor)

40
Q

What is an antagonist?

A

A ligand that binds to a receptor and prevents activation BY an agonist

41
Q

How does an antagonist change the cellular response?

A

inhibition - doesn’t allow signal transduction to occur

42
Q

How are agonists and antagonists similar?

A

make specific chemical contacts with receptors

43
Q

How do agonists and antagonists differ?

A

despite binding in a similar position only the chemical contacts made by an agonist are sufficient to cause a conformation change in the receptor

44
Q

How does adrenaline work?

A
  1. Acts as an agonist to activate the a GPCR called the Beta- adrenergic receptor
  2. Signal transduction
  3. Bronchodilation
45
Q

How does Insulin work?

A
  1. Acts as an agonist to activate the insulin receptor (a RTK)
  2. Signal transduction
  3. Glucose uptake
46
Q

Why are receptors so important in making drugs?

A

Chemical substances commonly act via receptor to change the cellular response

BIOC192 2024 (25 decks)

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