MBC Lecture 10 Enzymes Flashcards

0
Q

Describe the biological importance of enzymes

A
Structure
Enzymes
Signals (hormones)
Receptors
Molecular machines
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1
Q

Describe the features of enzymes

A

Reduce activation energy of a reaction
Active site with amino acid residues
Don’t change the position of equilibrium

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2
Q

What are three examples of how enzymes are important in medicine?

A

Drugs: Ralenza
Diagnosis and prognosis: Cardiovascular disease, monitor CK as a marker of heart attack
Diseases caused by under or over activity: Phenylketonuria

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3
Q

Describe a disorder caused by enzyme inactivity

A

Phenylketonuria

There is a mutation in the phenylalanine hydroxylase enzyme

These individuals can’t break down phenylalanine
Severe mental retardation
Treatment: remove phenylalanine from the diet

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4
Q

Describe how enzymes are important in diagnosis and prognosis of disease
Use an example to explain

A

Eg. Cardiovascular disease

This disease has elevated levels of CK, AST and LDH

By monitoring these enzymes, we can diagnose and monitor the disease

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5
Q

Which enzymes are present in individuals with cardiovascular disease?

A

CK
AST
LDH

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6
Q

Describe how enzymes are Important drug targets

A

Eg. Ralenza targets the neurominadase enzymes that help new influenza viruses break out of the host cell

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7
Q

Describe how enzymes are important for industry

Give an example

A

Food chemistry, agriculture, chemical engineering

Cheese production relies on chymosin

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8
Q

What is chymosin?

A

An enzyme that is vital for cheese production

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9
Q

What is Michaelis Menten good for?

A

Determining Vmax and Km (the concentration of substrate at which the enzyme is working at half it’s maximum possible speed

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10
Q

What is V0?

A

This is the initial rate of reaction

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11
Q

Describe how we determine Vmax and Km

A

Determine the rate of reaction as soon as substrate is added to a set amount of protein
Repeat for many concentrations of substrate

Plot a graph of [S] vs. V0

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12
Q

What is Lineweaver-Burk analysis?

A

This is taking the reciprocal of the M-M equation

It allows us to more clearly see the effect of inhibitors on enzyme activity

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13
Q

Describe the Michaelis Menten equation

A

.

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14
Q

What is the Lineweaver Burk equation?

A

.

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15
Q

List the four types of inhibition

A
Irreversible
Reversible:
Competitive
Uncompetitive
Mixed
16
Q

Describe irreversible inhibition

A

The inhibitor covalently binds to the active site of the enzyme

17
Q

Describe competitive inhibition

A

An inhibitor binds to the active site of the enzyme

18
Q

Describe uncompetitive inhibition

A

An inhibitor binds to some other site on the enzyme after the substrate has bound.
The substrate is not catalysed, and can’t be ejected

19
Q

Described mixed inhibition

A

Theis is when the inhibitor can bind either before or after the substrate has bound to the active site

20
Q

Draw all of the different graphs

A

.

21
Q

In which enzyme is there a mutation in phenylketonuria

A

Phenylalanine hydroxylase

22
Q

Km increases
Vmax stays the same

Which type of inhibition?

A

Cmpetitive

23
Q

Km increases
Vmax decreases

Which type of inhibition?

A

Mixed

24
Q

Km decreases
Vmax decreases

Which type of inhibition?

A

Uncompetitive