7-Enzymes (more)

Question 1

What oxidoreductases do?

Answer 1

Oxidoreductases catalyze oxidation/reduction reactions; transfer of H and O atoms or electrons from one substance to another

Question 2

What transferases do?

Answer 2

Transferases catalyze the transfer of functional groups from one substance to another

Question 3

What hydrolases do?

Answer 3

Hydrolases catalyze formation of two products from a

substrate by hydrolysis (splitting using water)

Question 4

What Lyases do?

Answer 4

Lyases catalyze non-hydrolytic addition or removal of
groups from substrates
C-C, C-N, C-O or C-S bonds may be cleaved

Question 5

What isomerases do?

Answer 5

Isomerases catalyze intramolecule rearrangement, i.e. isomerization changes within a single molecule

Question 6

What ligases do?

Answer 6

Ligases join together two molecules by synthesis of
new C-O, C-S, C-N or C-C bonds with simultaneous
breakdown of ATP

Question 7

What kind of bonds do enzymes have?

Answer 7

Enzyme structure is stabilised by many weak bonds
(e.g. H-bonds, electrostatic salt bridges, Van der Waals
and hydrophobic interactions)

Question 8

What special about the enzyme catalase?

Answer 8

Catalase has four identical subunits, each with catalytic activity

Question 9

How a protein can be transformed into a denatured state?

Answer 9

The weak bonds which stabilize enzyme
structure are easily broken [e.g. by heating the
protein, giving rise to a disorganised or tangled
structure in which the enzyme no longer has any
catalytic activity (inactive, ‘denatured’ state)