Lecture 11 - Enzyme Mechanisms Flashcards Preview

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Flashcards in Lecture 11 - Enzyme Mechanisms Deck (12):
0

Electron-rich functional group that donates an electron pair with an electrophile to form a bond

Nucleophile (Nu:)

1

Electron- deficient functional group that accepts an electron pair from a nucleophile to form a bond

Electrophile (E)

2

True or false? A lower dielectric environment increases the strength of electrostatic interactions.

True

3

What's the difference between specific acid or base and general acid or base?

Specific acid (H3O+)
Specific base (-OH)
General acid is a proton donor
General base is a proton acceptor

4

Bovine pancreatic protease that catalyzes the hydrolytic cleavage of peptide bond

Chymotrypsin

5

Name the steps in each phase (phase 1 and 2) of the enzyme mechanism

1. Positioning
2. His 57 is general base
3. Nucleophilic attack
4. Covalent intermediate
5. His 57 is general acid

6

What acts as a general base in chymotrypsin reaction to deprotonate the hydroxyl group of Ser-195 and make it a better nucleophile

His-57

7

What acts as a nucleophile and attacks the carbonyl group forming a covalent bond with the carbonyl carbon = covalent catalysis

Ser-195

8

What catalyzes the phosphorylation of glucose in a reversible reaction, involving Mg ion, ADP and ATP?

Hexokinase

9

What's the function of coenzymes?

Coenzymes aid in catalyzing reactions that could not be catalyzed with the functional groups present in amino acids

10

Name some of the common biological nuclophiles?

Oxygen anion, sulfur anion, carbanion, nitrogen anion, imidazole, hydroxide

11

Name some of the common biological electrophiles

Carbonyls, protonated imines, phosphorous in phosphate group, proton