Enzymes And Co-enzymes Flashcards

1
Q

What conditions do enzymes work in compared to industrial processes?

A

Enzymes work in relatively mild conditions, such as low pressure and mild temperatures.

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2
Q

What are nerve agents and give examples?

A

Nerve agents are chemical weapons, examples include sarin and Novichok.

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3
Q

What enzyme do nerve agents bind to at the neuromuscular junction?

A

Nerve agents bind to the active site of acetylcholinesterase.

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4
Q

What is the effect of nerve agents on acetylcholine (ACh) at the neuromuscular junction?

A

ACh is not degraded, leading to increased ACh available to bind to nicotinic acetylcholine receptors.

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5
Q

What happens to the motor end plate due to persistent depolarization caused by nerve agents?

A

The motor end plate becomes refractory, resulting in no more end plate potentials generated in skeletal muscle.

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6
Q

What are ribozymes?

A

Ribozymes are self-replicating RNA molecules

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7
Q

Where are ribozymes found and what is their function?

A

Ribozymes are present in the ribosome and catalyse the formation of peptide bonds during polypeptide synthesis.

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8
Q

What does the EC number signify?

A

The EC number indicates the class of reaction catalysed, with the first number representing the top level code.

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9
Q

True or False: Snake venom toxins can bind to the active site of acetylcholinesterase.

A

True.

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10
Q

What are the 7 main classes of enzymes

A

1- oxidoreductase
2- transferase
3- hydrolase
4- lyase
5- isomerase
6- ligase
7- translocases

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11
Q

Define cofactors

A

Inorganic ions, eg. Fe2+, Mg2+

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12
Q

Define coenzymes

A

Organic molecules, eg. NAD, NADP, FAD

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13
Q

Outline coenzymes

A

-many coenzymes derived from vitamin precursors & essential in the diet

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14
Q

What is a prosthetic group?

A

A coenzyme that tightly binds
-covalently bound cofactor

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15
Q

Define cosubstrates

A

-type of coenzymes
-loosely bound -> bind and unbind during catalysis

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16
Q

Define holoenzyme

A

Catalytically active enzyme with its cofactor/coenzyme

17
Q

Define apoenzyme

A

Protein moiety of enzyme without cofactor/coenzyme- inactive

18
Q

What is Gibbs free energy

A

A measure of the useable or useful energy of a system

19
Q

What are the components of a holoenzyme

A

The apoenzyme (inactive) + its coenzyme/ cofactor

20
Q

What are nucleophiles and electrophiles

A

Nucleophiles- donate electron pairs to form a chemical bond
Electrophiles- accept electron pairs

21
Q

What are the four enzyme catalytic strategies

A

-covalent catalysis
-general acid-base catalysis
-catalysis by approximation
-metal ion catalysis

22
Q

Outline covalent catalysis

A

Active site contains reactive group, which becomes covalently bonded to substrate during reaction

23
Q

Outline general acid-base catalysis

A

Transfer of protons (donate or accept) to or from intermediate

24
Q

Outline catalysis by approximation

A

Binding surface of enzyme brings two substrates into close proximity

25
Q

Outline metal ion catalysis

A

-metal ions can act as an electrophile and stabilise negative charge on intermediate
-or facilitate nucleophile formation by co-ordination
-or can act as bride between enzyme and substrate