Lecture 14 - Aspartate/Threonine/Isoleucine Synthesis Mechanism

Question 1

Step 1

Answer 1

Oxaloacetate -> aspartate

Question 2

Enzyme of step 1

Answer 2

Aspartate transaminase

Question 3

Cofactor of step 1

Answer 3

• PLP

- Glutamate -> alpha-ketoglutarate

Question 4

Step 2

Answer 4

Aspartate -> aspartyl phosphate

Question 5

Enzyme of step 2

Answer 5

Aspartate kinase

Question 6

Cofactor of step 2

Answer 6

ATP -> ADP

Question 7

Step 3

Answer 7

Aspartyl phosphate -> aspartate semi-aldehyde

Question 8

Enzyme of step 3

Answer 8

Aspartate semialdehyde dehydrogenase

Question 9

Cofactor of step 3

Answer 9

• NADPH + H+ -> NADP+

- H2O -> Pi

Question 10

Step 4

Answer 10

Aspartate semialdehyde -> homoserine

Question 11

Enzyme of step 4

Answer 11

Homoserine dehydrogenase

Question 12

Cofactor of step 4

Answer 12

NADPH + H+ -> NADP+

Question 13

Step 5

Answer 13

Homoserine -> homoserine phosphate

Question 14

Enzyme of step 5

Answer 14

Homoserine kinase

Question 15

Cofactor of step 5

Answer 15

ATP -> ADP

Question 16

Step 6

Answer 16

Homoserine phosphate -> threonine

Question 17

Enzyme of step 6

Answer 17

Threonine synthase

Question 18

Cofactor of step 6

Answer 18

H2O -> Pi

Question 19

Step 7

Answer 19

Threonine -> alpha-ketobutyrate

Question 20

Enzyme of step 7

Answer 20

Threonine dehydratase

Question 21

Cofactor of step 7

Answer 21

NH3 out

Question 22

Step 8

Answer 22

Alpha-ketobutyrate -> aceto-alpha-hydroxybutyrate

Question 23

Enzyme of step 8

Answer 23

Acetolactate synthase

Question 24

Cofactor of step 8

Answer 24

Pyruvate -> CO2

Question 25

Step 9

Answer 25

Aceto-alpha-hydroxybutyrate -> dihydroxymethylvalerate

Question 26

Enzyme of step 9

Answer 26

Acetolactate isomeroreducatase

Question 27

Cofactor of step 9

Answer 27

NADPH + H+ -> NADP+

Question 28

Step 10

Answer 28

Dihydroxymethylvalerate -> alpha-ketomethylvalerate

Question 29

Enzyme of step 10

Answer 29

Dihydroxy isovalerate dehydratase

Question 30

Cofactor of step 10

Answer 30

H2O out

Question 31

Step 11

Answer 31

Alpha-ketomethylvalerate -> isoleucine

Question 32

Enzyme of step 11

Answer 32

Branched chain amino acid transaminase

Question 33

Cofactor of step 11

Answer 33

- PLP | - Glutamate -> alpha-ketoglutarate

Question 34

What is important to note about steps 8-11?

Answer 34

Identical to the entire mechanism of valine synthesis