Chapter 19

Question 0

Turnover number

Answer 0

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

Question 1

Enzymes

Answer 1

> biological catalyst. -proteins

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

Question 2

Enzymes as proteins

Answer 2

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

Question 3

Active site

Answer 3

Fold or grove on enzymes surface where chemical reactions happen.

Question 4

Substrates

Answer 4

Reactant molecules

Question 5

Cofactors

Answer 5

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

Question 6

Function of coenzymes

Answer 6

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

Question 7

Enzymes: regulated

Answer 7

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

Question 8

Naming enzymes

Answer 8

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

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

Question 9

Oxidase

Answer 9

Catalyze an oxidation

Question 10

Dehydrogenase

Answer 10

Removes 2 hydrogen atoms

Question 11

Transaminase

Answer 11

Transfers amino group

Question 12

Kinase

Answer 12

Transfers phosphate group

Question 13

Lipase

Answer 13

Hydrolysis of lipids

Question 14

Protease

Answer 14

Hydrolysis of proteins

Question 15

Phosphatase

Answer 15

Hydrolysis of phosphate ethers (take phosphate off)

Question 16

Decarboxylase

Answer 16

Removes Carboxylic acid group as CO2

Question 17

Deaminase

Answer 17

Removes amino group

Question 18

Synthase

Answer 18

Synthesizes a new molecule

Question 19

Carboxylase

Answer 19

Adds carbon dioxide to a molecule (makes Carboxylic acid)

Question 20

How enzymes work

Answer 20

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

Question 21

Catalysis

Answer 21

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

Question 22

Enzyme reaction rate depends on:

Answer 22

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

Question 23

Feedback control

Answer 23

Product inhibits the first enzymes pathways

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

Question 24

Allosteric control

Answer 24

Built in regulatory site different from active site."anything else"

Question 25

Inhibition

Answer 25

Reversible :non covalent | irreversible :covalent (permanently attached) ex: penicillin

Question 26

Competitive/ non competitive reversible inhibition | "Active site"

Answer 26

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

Question 27

Population dynamics

Answer 27

Enzyme inhibition occurs in a population of many identical molecules. When an inhibitor bind to enzyme it become inactive, while others are still active.

Question 28

Enzyme regulation

Answer 28

Regulated by: •Removal of of covalent bonded part of enzyme [zymogens] •addition/removal of phosphate groups[phosphorylation]

Question 29

Zymogens (pro enzymes)

Answer 29

Enzymes are made inactive in in order to activate you must "CLEAVE"

Question 30

Phosphorylation | Most common

Answer 30

Addition of phosphate causes a shape change in enzymes that can activate the enzymes

Question 31

Fat soluble vitamins

Answer 31

A D E & K - mostly hydrocarbon - can overdose - stored in fat - difficult to remove from body

Question 32

Vitamin E

Answer 32

Tocopherol :antioxidant that protects membranes from free radical oxygen damage

Question 33

Water soluble act as:

Answer 33

Coenzymes

Question 34

Antioxidants

Answer 34

Substances to prevent oxidation >remove free radicals > vitamin C E, b-carotene, selenium >phenols are antioxidants

Question 35

Minerals

Answer 35

Inorganic ions >cofactors : metal ions >most are divalent cations

Question 36

Vitamins C

Answer 36

Antioxidant; protects aqueous components of body& retires vitamin E

Question 37

Phosphodiesterase

Answer 37

Breaks down cAMP

Question 38

Agonist & antagonist

Answer 38

Agonist: activates receptor Antagonist: prevents/blocks receptor