Chapter 19 Flashcards

(39 cards)

0
Q

Turnover number

A

Number of reactions per second
> speed of enzymology reactions measured by this
> most catalyze 100-1000 per sec

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1
Q

Enzymes

A

> biological catalyst. -proteins

  • make reactions happen faster
  • chiral
  • highly specific(catalyze only one type of reaction)
  • produces one product, w/no side reactions
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2
Q

Enzymes as proteins

A
water soluble: globular proteins
Insoluble :fibrous 
ex: RNA
>specific shape
>flexible 
>Denaturation 
>side chain interactions
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3
Q

Active site

A

Fold or grove on enzymes surface where chemical reactions happen.

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4
Q

Substrates

A

Reactant molecules

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5
Q

Cofactors

A

Non-protein part of an enzyme that is essential to enzymes catalytic activity.
>metal ion
>coenzyme
•vitamins provide coenzyme cofactors

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6
Q

Function of coenzymes

A

Coenzymes are bound to active site, participate in chemical reaction
>cofactors and coenzymes provide a charge or functional groups needed for reaction to occur

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7
Q

Enzymes: regulated

A

Regulation allows cells to respond to changes
•Activity is carefully regulated:
>turned on and off
>reaction occurs by interaction w/specific molecules

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8
Q

Naming enzymes

A
  • ase” newer names( 2parts)
    1) substrate 2) type of reaction

-in” older names (1 part)
Function or name

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9
Q

Oxidase

A

Catalyze an oxidation

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10
Q

Dehydrogenase

A

Removes 2 hydrogen atoms

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11
Q

Transaminase

A

Transfers amino group

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12
Q

Kinase

A

Transfers phosphate group

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13
Q

Lipase

A

Hydrolysis of lipids

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14
Q

Protease

A

Hydrolysis of proteins

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15
Q

Phosphatase

A

Hydrolysis of phosphate ethers (take phosphate off)

16
Q

Decarboxylase

A

Removes Carboxylic acid group as CO2

17
Q

Deaminase

A

Removes amino group

18
Q

Synthase

A

Synthesizes a new molecule

19
Q

Carboxylase

A

Adds carbon dioxide to a molecule (makes Carboxylic acid)

20
Q

How enzymes work

A

> substrate fits into active site
change it shape to make reactions happen
bonds broken & new bonds are made
product released

21
Q

Catalysis

A
>enzymes act as a catalyst because they can:
•bring substrate together
•hold substrate
•provide acidic or basic groups 
•induce strains in bonds
22
Q

Enzyme reaction rate depends on:

A

> substrate concentration(more enzymes faster reaction)
temperature (increases with increasing temp)
pH

23
Q

Feedback control

A

Product inhibits the first enzymes pathways

{1>2>3>4} 4 inhibits #1

24
Allosteric control
Built in regulatory site different from active site."anything else"
25
Inhibition
Reversible :non covalent | irreversible :covalent (permanently attached) ex: penicillin
26
Competitive/ non competitive reversible inhibition | "Active site"
Reversible competitive : inhibitor bind to active site and compete w/substrate reversible non competitive:inhibitors bind to enzyme not @ active site; often used as medicine
27
Population dynamics
Enzyme inhibition occurs in a population of many identical molecules. When an inhibitor bind to enzyme it become inactive, while others are still active.
28
Enzyme regulation
Regulated by: •Removal of of covalent bonded part of enzyme [zymogens] •addition/removal of phosphate groups[phosphorylation]
29
Zymogens (pro enzymes)
Enzymes are made inactive in in order to activate you must "CLEAVE"
30
Phosphorylation | Most common
Addition of phosphate causes a shape change in enzymes that can activate the enzymes
31
Fat soluble vitamins
A D E & K - mostly hydrocarbon - can overdose - stored in fat - difficult to remove from body
32
Vitamin E
Tocopherol :antioxidant that protects membranes from free radical oxygen damage
33
Water soluble act as:
Coenzymes
34
Antioxidants
Substances to prevent oxidation >remove free radicals > vitamin C E, b-carotene, selenium >phenols are antioxidants
35
Minerals
Inorganic ions >cofactors : metal ions >most are divalent cations
36
Vitamins C
Antioxidant; protects aqueous components of body& retires vitamin E
37
Phosphodiesterase
Breaks down cAMP
38
Agonist & antagonist
Agonist: activates receptor Antagonist: prevents/blocks receptor