Enzymes II

Question 1

Nucleophilicity is related to

Answer 1

basicitiy

Question 2

Nucleophilies can

Answer 2

covanteltly bond to electron deficient centers

Question 3

electrophilic group are.

Answer 3

electron deficient so they love electrons

Question 4

Some nucleophiles groups are

Answer 4

hydroxyl group, sulfhydryl group, amino group, imidazole group

Question 5

Some electrophilles groups are

Answer 5

protons, metal ions, carbonyl carbon atom, cationic imine

Question 6

Partial proton donation is also

Answer 6

general acid catalysis

Question 7

abstraction is also known as

Answer 7

general base catalysis

Question 8

What amino acids participate in acid-base catalysis?

Answer 8

Asp, Glu, Lys, Arg, and His

Question 9

What makes a good catalyst

Answer 9

good leaving groups

Question 10

for a good catalyst, reverasibily

Answer 10

of the bond fromed is key

Question 11

A good catalyst correlates with

Answer 11

polarizability and how mobile electrons are

Question 12

highly polarized equals

Answer 12

highly breakables

Question 13

Step 1 in RNase A for His 12

Answer 13

abstracts proton from 2’-OH

Question 14

His 12 causes

Answer 14

a nucleophillic attack on P

Question 15

His 119 step 1

Answer 15

protonates a leaving group causing bond breaking

Question 16

Step 2 for RNase A His 119

Answer 16

deprives H+ from H2O which results in OH- attacking P

Question 17

Step 2 His 12

Answer 17

donates its proton → 2’,3’ cyclic intermediate is broken.

Question 18

Covalent catalysis is via

Answer 18

transient formation of covalent ES intermediate

Question 19

covalent catalysis is usually

Answer 19

a nuucleophile attacjs abn electrophile and forms covalent bond with it

Question 20

What are the 2 classes of metal ion catalysis

Answer 20

metalloenzymes and metal-activated enzymes

Question 21

Decarboxylation of acetoacetate is by

Answer 21

primary amine (via Schiff bond)

Question 22

What is the first step Decarboxylation of acetoacetate

Answer 22

Nucleophilic attack by amine
 formation of covalent bond

Question 23

What is step 2 of the Decarboxylation of acetoacetate

Answer 23

Catalyst becomes electron-
deficient  e - from reaction cente

Question 24

Metal ion catalysis acts in 3 ways

Answer 24

1. Bind to substrates (orient properly for reaction).
2. Transiently change redox state (mediate redox reaction).
3. Stabilize/shield negative charges.

Question 25

Metalloenzymes are

Answer 25

tightly bound and usually transition metals

Question 26

Examples of matelloenzymes

Answer 26

Fe 2+ , Fe 3+ , Cu 2+ , Zn 2+ , Mn 2+ , Co 2+

Question 27

Metal activated enzymes

Answer 27

loosely bound metal from solution, alkaline

Question 28

Zn2+ is coordinated

Answer 28

by the imidazole of 3 His and a water

Question 29

Binding to E forces

Answer 29

substrate in a orient way which is rotational, translational motions cease and actives groups face each other

Question 30

Proximity and orientation effects comes at the expense of

Answer 30

lost of entropy and is compensated by the binding energy of E to S

Question 31

theres a preferential binding to the

Answer 31

ES -transition state

Question 32

the transition state binds

Answer 32

the enzyme’s active site tighthly and acts a potent inhibtor

Question 33

The transition state analog helps

Answer 33

confirming the structure of the natural transition state