Enzymes Quiz

Question 1

Transferase: reaction and enzyme name

Answer 1

Transfer of functional groups from one molecule to another; Reactant receiving functional group + functional group + transferase (named in direction written)

Question 2

Hydrolase: reaction and enzyme name

Answer 2

Bond cleavage or formation with the addition or removal of water; Compound to be cleaved + hydrolase (named in direction of hydrolase)

Question 3

Lyase: reaction and enzyme name

Answer 3

Group elimination to form a double bond (can result in C-C bond cleavage); If no C-C bonds broken: compounds with single bond + lyase
Or
Compound with C-C bond cleaved + synthase (always in direction of double bond formation)

Question 4

Isomerase: reaction and enzyme name

Answer 4

Intramolecular rearrangements; Reactant + Isomerase (named in direction written)

Question 5

Ligase: reaction and enzyme name

Answer 5

Bond formation (or breaking) coupled to ATP hydrolysis (or formation); Both reactants + ligase
Compound formed + synthetase
(Always in direction of ATP (or GTP) hydrolysis)

Question 6

Proximity and orientation: definition and how to recognize

Answer 6

Substrate is bound in the proper alignment to and next to catalytic amino acids
Substrate binding to active site

Question 7

Purpose of proximity and orientation

Answer 7

Increase reaction rate by limiting diffusion and maximizing alignment of reacting functional groups

Question 8

Preferential binding of the TS: definition and how to recognize

Answer 8

Enzymes bind transition state with higher affinity than substrates or products
Additional contacts made to unstable intermediate (TS) relative to substrate/product

Question 9

Purpose of preferential binding of the TS

Answer 9

Increase reaction rates by lowering transition state energy

Question 10

Acid/Base Catalysis definition and how to recognize

Answer 10

Enzyme donates or accepts a proton (can be to another amino acid or substrate)
A protonated amino acid becomes deprotonated/a deprotonated amino acid becomes protonated

Question 11

Purpose of acid/base catalysis

Answer 11

Stabilize leaving groups, increase nucleophilicity, stabilize transition state

Question 12

Covalent catalysis definition and how to recognize

Answer 12

Enzyme forms a covalent bond with the substrate

Deprotonated amino acid nucleophilically attacks substrate (forming a covalent bond)

Question 13

Purpose of covalent catalysis

Answer 13

Facilitate bond cleavage, provides a new reaction pathway

Question 14

Electrostatic catalysis definition and how to recognize

Answer 14

Charge on the enzyme interacts with a neighboring charge

Charge on the enzyme interacts with neighboring charge

Question 15

Purpose of electrostatic catalysis

Answer 15

Substrate specificity/orientation, stabilize charges forming

Question 16

Metal ion catalysis definition and how to recognize

Answer 16

Metal ion in the active site participates in catalysis

Metal ion in the active site

Question 17

Purpose of metal ion catalysis

Answer 17

Charge stabilization, water ionization, electron transfer

Question 18

Oxidoreductase: reaction and enzyme name

Answer 18

Transfer of electrons from one molecule to another; Electron donor:electron acceptor + oxidoreductase (named in direction written)

Question 19

Dehydrogenase subclass: reaction and to which enzyme class it belongs

Answer 19

Transfer a hydride ion (usually to an acceptor); oxidoreductase

Question 20

Oxidase common name: reaction and to which enzyme class it belongs

Answer 20

Transfer electrons to oxygen; oxidoreductase

Question 21

Reductase common name: reaction and to which enzyme class it belongs

Answer 21

Transfer of a hydride ion (usually from an acceptor); oxidoreductase

Question 22

Kinase subclass: reaction and to which enzyme class it belongs

Answer 22

Transfer of phosphate (phosphoryl group) between any compound and the adenylates (AMP, ADP, ATP); transferase

Question 23

Aminotransferase (Transaminase) subclass: reaction and to which enzyme class it belongs

Answer 23

Transfer of an amino group between compounds; transferase

Question 24

Phosphatase subclass: reaction and to which enzyme class it belongs

Answer 24

Hydrolysis of a single bond between compound and a phosphate group producing inorganic phosphate; hydrolase

Question 25

Protease subclass: reaction and to which enzyme class it belongs

Answer 25

Hydrolysis of peptide bond; hydrolase

Question 26

Glycosidase subclass: reaction and to which enzyme class it belongs

Answer 26

Hydrolysis of glycosidic bond; hydrolase

Question 27

Synthase subclass: reaction and to which enzyme class it belongs

Answer 27

Breaking of a double bond of one compound and concomitant formation of a new carbon-carbon bond with a second compound to form a new single compound; lyase

Question 28

Hydratase subclass: reaction and to which enzyme class it belongs

Answer 28

Removal of water to form a double bond; lyase

Question 29

Mutase subclass: reaction and to which enzyme class it belongs

Answer 29

Apparent migration of a functional group from one position on a compound to another position on the same compound; isomerase