Final: Co-factors, Mnemonics, etc. (Ben) Flashcards
What prosthetic grp do aminotransferases use?
PLP
What is the co-factor for Glu Dehydrogenase?
NAD+ or NADPH
- NAD+ in the Glu dehydrogenation direction
- NADPH when re-aminating alpha-KG to Glu
What is the coenyzme for serine and threonine dehydratases?
PLP
What does glutamine synthetase require for formation of Gln from Glu?
ammonia and ATP
(giving ADP + Pi)
What is the co-factor for dihydrofolate reductase?
2 NADPH
2 reductions … folate to H2F to H4F
What is the cofactor for Methylene-H4F Reductase?
NADH
What is the prosthetic group for Homocysteine Methyltransferase?
Methyl-B12
What is the co-factor for Met adenosyl transferase?
How is it used differently here than in most reactions?
ATP
Here, all 3 Ps are broken off to get the adenosine for transfer to Met.
What is the co-factor for cystathionine synthase?
PLP
What are the cofactors for the enzymes which convert Met/Thr/Val/Ile from their alpha-ketoacid intermediates into succinyl-CoA?
(3 enzymes)
- BC-alpha-KA DH = TPP, lipoic acid, FAD, NAD, CoA
- propionyl-CoA carboxlase = biotin
- methylmalonyl-CoA mutase = 5-adenosyl cobalamine (B12)
What co-factor do both Serine and Threonine Dehydratases use?
PLP
What are the co-factors for serine hydroxymethyltransferase?
PLP
and
H4F ( becomes methylene-H4F )
Co-factor for Glu Decarboxylase?
PLP
What is the cofactor for Phe OHase?
And how is it formed?
H4F-Biopterin
-
H4F-Biopterin Reductase
- uses NADPH to reduce H2F-Biopterin
What co enzyme is used by dihydro-orotate dehydrogenase?
NAD+
What co-factor do tyrosine hydroxylase and tryptophan hydroxylase use?
H4-Biopterin
What co-factor does Dopamine B-Hydroxylase use?
ascorbic acid
(vitamin C)
What is the cofactor for COMT?
(bonus… what does the enzyme make?)
SAM
- methylates an NE metabolism intermediate to form MHPG the urinary indicator of CNS NE function
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?
- VII plus TF is extrinsic tenase complex
- X plus V is prothrombinase complex
Which special domain do some clotting factors contain which enhances membrane binding?
Which factors have it?
What else has it?
Gla domain
- II, VII, IX and X have it
(2, 7, 9, 10)
- protein C and protein S also have it
What co factor does vitamin k oxidoreductase use?
NADPH
(NOT vitamin K! that is used by gamma carboxylase… VKOR uses NADPH to reduce vit K from VKO to VKH2 form)
What are the 3 most common bleeding disorders and their causes?
Why aren’t these fatal?
- Hemophilia A - factor VIII deficiency
- Hemophilia B - factor IX defic.
- 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.
What are the non-essential AAs?
Semi-essential?
A A A C G G G Pro S T
- Alanine, Aspartate, Asparagine
- Cysteine
- Glutamine, Glutamate, Glycine
- Proline
- Serine
- Tyrosine
- Semi-essential: Arginine
Which AAs can not be transaminated?
Lys, Thr, Pro and HydroxyPro
Which AAs can form succinyl-CoA?
What must they first become to enter the succinyl-CoA forming pathway?
(And how do they get there?)
Met, Thr, Val, Ile
(Met Three Valiant Islanders)
- all first become α-ketoacids
- Met –(SAM cycle)–> HCys –(Cysta. Synthase)–> α-ketobutyrate
- Thr –(Thr Dehydratase)–> α-ketobutyrate
- Val, Ile –> α-ketoacids
Which AAs form oxaloacetate?
How?
Asp and Asn
- Asn + H2O –(asparaginase)–> Asp + NH4+
- —(ASAT)—> Oxaloacetate
- remember ASAT uses PLP
Which AAs form pyruvate?
Two of them do so in one reaction… which?
Ala, Ser, Gly, Cys
Al + Sarah Glide (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
Which AAs form alpha-ketoglutarate?
Generally, how?
Glu/Gln, Pro, Arg, His

(Gluttonous Professionals Are History)
- 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 )