Final: Co-factors, Mnemonics, etc. (Ben)

Question 1

What prosthetic grp do aminotransferases use?

Answer 1

PLP

Question 2

What is the co-factor for Glu Dehydrogenase?

Answer 2

NAD+ or NADPH

• NAD+ in the Glu dehydrogenation direction
• NADPH when re-aminating alpha-KG to Glu

Question 3

What is the coenyzme for serine and threonine dehydratases?

Answer 3

PLP

Question 4

What does glutamine synthetase require for formation of Gln from Glu?

Answer 4

ammonia and ATP

(giving ADP + Pi)

Question 5

What is the co-factor for dihydrofolate reductase?

Answer 5

2 NADPH

2 reductions … folate to H2F to H4F

Question 6

What is the cofactor for Methylene-H4F Reductase?

Answer 6

NADH

Question 7

What is the prosthetic group for Homocysteine Methyltransferase?

Answer 7

Methyl-B12

Question 8

What is the co-factor for Met adenosyl transferase?

How is it used differently here than in most reactions?

Answer 8

ATP

Here, all 3 Ps are broken off to get the adenosine for transfer to Met.

Question 9

What is the co-factor for cystathionine synthase?

Answer 9

PLP

Question 10

What are the cofactors for the enzymes which convert Met/Thr/Val/Ile from their alpha-ketoacid intermediates into succinyl-CoA?

(3 enzymes)

Answer 10

1. BC-alpha-KA DH = TPP, lipoic acid, FAD, NAD, CoA
2. propionyl-CoA carboxlase = biotin
3. methylmalonyl-CoA mutase = 5-adenosyl cobalamine (B12)

Question 11

What co-factor do both Serine and Threonine Dehydratases use?

Answer 11

PLP

Question 12

What are the co-factors for serine hydroxymethyltransferase?

Answer 12

PLP

and

H4F ( becomes methylene-H4F )

Question 13

Co-factor for Glu Decarboxylase?

Answer 13

PLP

Question 14

What is the cofactor for Phe OHase?

And how is it formed?

Answer 14

H4F-Biopterin

• H4F-Biopterin Reductase
  
  • uses NADPH to reduce H2F-Biopterin

Question 15

What co enzyme is used by dihydro-orotate dehydrogenase?

Answer 15

NAD+

Question 16

What co-factor do tyrosine hydroxylase and tryptophan hydroxylase use?

Answer 16

H4-Biopterin

Question 17

What co-factor does Dopamine B-Hydroxylase use?

Answer 17

ascorbic acid

(vitamin C)

Question 18

What is the cofactor for COMT?

(bonus… what does the enzyme make?)

Answer 18

SAM

• methylates an NE metabolism intermediate to form MHPG the urinary indicator of CNS NE function

Question 19

In the extrinsic pathway of thrombin activation…

What is the “cofactor” for factor VII?

What is the “cofactor” for factor X?

And what complexes do these form with their cofactors?

Answer 19

• VII plus TF is extrinsic tenase complex
• X plus V is prothrombinase complex

Question 20

Which special domain do some clotting factors contain which enhances membrane binding?

Which factors have it?

What else has it?

Answer 20

Gla domain

• II, VII, IX and X have it

(2, 7, 9, 10)

• protein C and protein S also have it

Question 21

What co factor does vitamin k oxidoreductase use?

Answer 21

NADPH

(NOT vitamin K! that is used by gamma carboxylase… VKOR uses NADPH to reduce vit K from VKO to VKH2 form)

Question 22

What are the 3 most common bleeding disorders and their causes?

Why aren’t these fatal?

Answer 22

1. Hemophilia A - factor VIII deficiency
2. Hemophilia B - factor IX defic.
3. Hemophilia C - factor XI defic.

(so 8, 9, 11 in that order)

Not fatal because they just play a part in positive feedback loops of the extrinsic pathway but aren’t essential to its function.

Question 23

What are the non-essential AAs?

Semi-essential?

Answer 23

A A A C G G G Pro S T

• Alanine, Aspartate, Asparagine
• Cysteine
• Glutamine, Glutamate, Glycine
• Proline
• Serine
• Tyrosine
• Semi-essential: Arginine

Question 24

Which AAs can not be transaminated?

Answer 24

Lys, Thr, Pro and HydroxyPro

Question 25

Which AAs can form **succinyl-CoA**? What must they first become to enter the succinyl-CoA forming pathway? (And how do they get there?)

Answer 25

**Met, Thr, Val, Ile** ## Footnote (Met Three Valiant Islanders) - all first become α-ketoacids * Met --(SAM cycle)--\> HCys --(Cysta. Synthase)--\> α-keto**_butyrate_** * Thr --(Thr Dehydratase)--\> α-keto**_butyrate_** * Val, Ile --\> α-ketoacids

Question 26

Which AAs form **oxaloacetate**? How?

Answer 26

**Asp** and **Asn** * **Asn** + H₂O --(_asparaginase_)--\> **Asp** + NH₄⁺ * ---(_ASAT_)---\> Oxaloacetate * remember ASAT uses _PLP_

Question 27

Which AAs form pyruvate? Two of them do so in _one reaction_... which?

Answer 27

**Ala, Ser, Gly, Cys** ## Footnote _Al_ + **_Sar_**ah **_Gl_**ide (into the) _Cysteine_ (chapel) * _Alanine_ becomes pyruvate directly via ALAT * remember ALAT _uses PLP_ * _Serine_ _Dehydratase_ * Serine ---\> Pyruvate + NH₄⁺ * also _uses PLP_, water is removed but then re-used

Question 28

Which AAs form _alpha-ketoglutarate_? Generally, how?

Answer 28

**Glu/Gln, Pro, Arg, His** ## Footnote (**_Glu_**tto**_n_**ous **_Pro_**fessionals **_Ar_**e **_His_**tory) * all are first _converted to glutamate_ which can be _transaminated_ to alpha-KG * ( structure-wise ... notice that it is Glu with a =O replacing the amine )