Enzyme Kinetics

Question 1

Oxidoreductase

Answer 1

Reaction: Transfer of Electrons
A- + B -> A + B-
Alcohol dehydrogenase

Question 2

Transferases

Answer 2

Reaction: Transfer of functional groups
A-B + C -> A + B-C
Hexokinase

Question 3

Hydrolases

Answer 3

Reaction: Hydrolysis Reactions
A_B + H20 -> A-H + B-OH
Trypsin

Question 4

Lysases

Answer 4

Reaction:Cleavage of C-C, C-O, C-N etc, formation of double bonds
Pyruvate decarboxylase

Question 5

Isomerases

Answer 5

Reaction: Transfer of groups within a molecule
Maleate isomerase

Question 6

Ligases or synthases

Answer 6

Reaction: Bond formation coupled to ATP hydrolysis
A + B -> A-B
Pyruvate carboxylase

Question 7

Why is the activation energy barrier lowered?

Answer 7

• Enzymes hold the substrates at certain positions and angles, improving reaction rate
• Formation of the enzyme-substrate complex may cause slight changes, promoting reactivity
• Multisubstrate enzyme-catalysed reactions, holding reaction regions of substrates closer together

Question 8

Commercial Enzymes

Answer 8

Amylase - produce glucose from starch
Tyrosine - cheese making
Proteolytic enzymes - washing powders
Glucose isomerase - fructose from glucose