Term 1- Lec 10- Enzymes Flashcards

1
Q

The 6 types of enzymatic reactions

A

Hydrolases, Ligases, Lyases, Oxidoreductases, Transferases, and Isomerases

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2
Q

Hydrolases

A

Cleave bonds by the addition of water

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3
Q

Ligases:

A

Form bonds between C and O, S, and N coupled with hydrolysis of high energy phosphates

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4
Q

Lyases:

A

Cleave C-C, C-S, and certain C-N

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5
Q

Oxidoreductases:

A

Catalyse oxidation-reduction reactions

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6
Q

Transferases:

A

Transfer C-, N- and P- containing groups

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7
Q

Isomerases:

A

Catalyze racemization of optical or geometric isomers

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8
Q

Cofactor

A

A small molecule required for the catalytic activity of an enzyme

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9
Q

Coenzyme

A

An organic cofactor ie. vitamins

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10
Q

Cosubstrate

A

When the cofactor only transiently binds to the enzyme

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11
Q

Prosthetic group

A

When the cofactor is permanently associated with the enzyme, either covalently or non-covalently

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12
Q

Holoenzyme

A

Catalytically active enzyme-cofactor complex

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13
Q

Apoenzyme

A

Inactive protein lacking the cofactor

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14
Q

Glycopeptidyl Transferase (GT)

A

Penecillin acts as a competitive inhibitor and covalently binds the active site, rendering it useless

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15
Q

Catalysis by proximity

A

Enzyme creates local high concentration of substrates and orients them correctly for bonding

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16
Q

Covalent catalysis

A

Enzyme forms a transient covalent bond with the substrate (typical in transferases)

17
Q

Catalysis by strain

A

Binds the substrate and puts it in an unfavor position to weaken the bond, making it easier to break the bond

18
Q

Mechanism for general acid-base catalysis

A

Side chains or prosthetic groups mediate proton transfer/binding between E and S/T

19
Q

Effect of substrate concentration on rxn rates

A

The rxn rate increases with concentration increase until it reaches a maximum level of saturation.

20
Q

Effect of enzyme concentration on rxn rates

A

More enzyme = faster rate

21
Q

effect of pH on rxn rate

A

environmental pH can strongly affect a rxn rate, with every enzyme having it’s own optimal pH for functioning

22
Q

Effect of denaturation on rxn rate

A

Denaturation causes enzymes to lose shape, thus function. pH, temperature, heavy metals, organic solvents, or mechanical mixing can cause it

23
Q

Effect of temperature on rxn rate

A

High temperatures increase chances of molecular colisions. At a certain high temperature, proteins begin to denature though. Low temps slow rxns.

24
Q

What does stereospecificity mean in enzymes?

A

They can tell D and L enantiomers apart and will only bind to one enantiomer of a molecule.