Sulfur and Aromatic AA Metabolism Flashcards
Name 3 major products that Trp is used to make.
- serotonin
- melatonin
- niacin
Where are Met residues usually found?
in the center of the protein
What aa is used to produce S-adenosylmethionine (SAM), a high energy storage unit?
methionine
How is hyperhomocysteinemia treated?
- folate
- B6
- B12
_____ is hydroxylated by phenylalanaine hydroxylase to produce Tyr using BH4 as a cofactor.
Phe
What is unique about cysteine?
it can form disulfide bonds –> strength
What is cysteinuria?
kidney stones –> renal failure due to defective cysteine transporter –> crystallization in urea
What is a tyrosinemia?
a defect in tyrosine degradation
Is methionine essential?
yes
Phe and Tyr are metabolized to _____ or ______.
- fumarate
- acetoacetate
What are the 2 sulfur containing aa’s?
- methionine
- cysteine
Phe is hydroxylated by phenylalanaine hydroxylase to produce _____ using BH4 as a cofactor.
Tyr
What can elevated homocysteine lead to?
- vascular disease
- impaired wound healing
- CA
What is the tx for homocystinuria?
vitamin B6
Trp is metabolized to ____ or _____.
- pyruvate
- acetyl-CoA
_____ is metabolized to pyruvate or acetyl-CoA.
Trp
Tyr is hydroxylated by ______ to produce DOPA using BH4.
tyrosine hydroxylase
What is S-adenosylmethionine (SAM) used for?
- methylation (DNA, proteins, NE–>epi)
- epigenetics
- host defense
- CA development
- fetal development
- tx for depression
_____ is hydroxylated by tyrosine hydroxylase to produce DOPA using BH4.
Tyr
This is a defect in phenylalanine hydroxylase –> build up of alternate byproducts (phenylacetate, phenylpyruvate).
phenylketonuria (PKU)
This disease causes kidney stones –> renal failure due to defective cysteine transporter –> crystallization in urea.
cysteinuria
What is tetrahydrofolate (THF) synthesized from?
vitamin B9 (folic acid)
What aa can form disulfide bonds?
cysteine
Phe is hydroxylated by ______ to produce Tyr using BH4 as a cofactor.
phenylalanaine hydroxylase
DOPA can be metabolized into _____ and _____.
- catecholamines (DOPA, DA, NE, epi)
- melanin
Where are Cys residues typically found?
in the active site
What is phenylketonuria (PKU)?
a defect in phenylalanine hydroxylase –> build up of alternate byproducts (phenylacetate, phenylpyruvate)
What is hyperhomocysteinemia?
elevated levels of homocysteine (bad)
This is a defect in cystathione-b-synthase (CBS) so homocysteine cannot be converted to cystathione –> mental retardation, osteoporosis, vascular disease.
homocystinuria
Name 3 aromatic aa’s.
- tryptophan
- phenylalanine
- tyrosine
What is homocystinuria?
a defect in cystathione-b-synthase (CBS) so homocysteine cannot be converted to cystathione –> mental retardation, osteoporosis, vascular disease
Is cysteine essential?
no
What is a cofactor for trp hydroxylation?
tetrahydrobiopterin (BH4)
___ and ____ are metabolized to fumarate or acetoacetate.
- Phe
- Tyr
Tyr is hydroxylated by tyrosine hydroxylase to produce _____ using BH4.
DOPA
What is required for the converstion of homocysteine –> methionine?
- THF
- vitamin B12
This peptide’s functions include:
- it allows for proper folding and disulfide bond formation
- a redox buffer
- a cofactor
- protects against ROS
glutathione (GSH)
What is unique about methionine?
it’s used to produce S-adenosylmethionine (SAM) –> high energy storage unit
What is the tx for cysteinuria?
acetazolamide
What is the function of glutathione (GSH)?
- it allows for proper folding and disulfide bond formation
- a redox buffer
- a cofactor
- protects against ROS
What is the term for elevated levels of homocysteine?
hyperhomocysteinemia
