Enzyme Classes

Question 1

Oxidoreductases

Answer 1

• transfer of electrons; one substrate is oxidized and the other is reduced
• could be two hydrogen atoms to form or close a double bond or a hydride transferred (typically to an electron carrier)(

Question 2

Transferases

Answer 2

• group transfer reactions
• two substrates; a “piece” of one is moved to the other
• Kinases: typically involve ATP hydrolysis and facilitate the transfer of phosphate groups

Question 3

Hydrolases

Answer 3

• Hydrolysis reactions (transfer of functional groups to water)
• typically break down molecules/polymers into individual subunits or smaller pieces
• use water to hydrolyze covalent bonds

Question 4

Ligases

Answer 4

• ligate = “tie together”
  
  • formation of covalent bonds (C-C, C-S, C-O, and C-N) bonds by condensation
• ​reactions coupled to ATP cleavage
• Ex: promotes coupling of glucose to itself to form glycogen or coupling amino acids to peptide chains

Question 5

Isomerases

Answer 5

• transfer of groups within molecules to yield isomeric forms
• rearrange molecules; only the connection of atoms in the molecule are changed, nothing is added or taken away

Question 6

Lyases

Answer 6

• cleavage of C-C, C-O, C-N, or other bonds by elimination, leaving double bonds or rings, or addition of groups to double bonds
• involve reactions where double bonds are formed by the removal of groups (water or ammonia)
• can also add groups (water or ammonia) to close a double bond