Special Products Flashcards
What energy level are resting muscles in? What happens to creatine?
high ATP concentration, creatine is phosphorylated by creatine kinase»phosphocreatine
What energy level are exercising muscles in? What happens to creatine?
low ATP concentration, ATP is re-generated by creatine phosphate and ADP
What amino acids are needed to make creatine?
glycine and arginine
How does the body ensure there’s enough energy for continued muscle contraction?
uses phosphocreatine to re-generate ATP
How is creatiNINe made?
spontaneous cyclization of storage creatine
How is creatinine excreted?
proportional to muscle mass of the body
How can levels of creatinine be used to suspect kidney function impair?
sudden increase in creatinine usually is indicative of decreased kidney function
How do treatments of defect in creatine synthesis and defect in creatine uptake differ?
treatment for defect in creatine synthesis: creatine supplement
treatment for defect in creatine uptake: none
- hypotonia (lack of muscle tone) but displays little skeletal or cardiac muscle pathology
- also exhibit variety of neurological symptoms include epileptic seizures and intellectual disability
symptoms of both defects in creatine synthesis and uptake
What special products can be made from tyrosine?
catacholamines: DOPA, dopamine, norepinephrine and epinephrine
thyroid hormones: T3 and T4
melanin
How is DOPA made?
from tyrosine, catalyzed by tyrosine hydroxylase, requires co-factor THBtn
How is dopamine made?
from DOPA, catalyzed by DOPA decarboxylase
How is norepinephrine made?
from dopamine, catalyzed by dopamine beta-hydroxylase
How is epinephrine made?
from norepinephrine, catalyzed by norepinephrine N-methyltransferase
Where is dopamine made?
dopaminergic neurons
Where is norepinephrine made?
sympathetic neurons
Where is epinephrine made?
adrenal medulla
How is melanin made?
2 step process catalyzed by tyrosinase:
tyrosine»DOPA»Dopaquinone» either eumelanin or pheomelanine
- loss of function to tyrosinase caused by mutations to TYR gene
- major complications include impaired vision and early appearance of skin tumors
Oculocutaneous albinism type I
What disease is associated with dengeneration of dopaminergic neurons? What is the treatment?
Parkinson’s - can’t make dopamine
Treatement: administration of DOPA, relieves symptoms but not a cure
What are the special products made from tryptophan?
serotonin, melatonin, niacin
tryptophan in turkey makes you sleepy and so does melatonin
What enzyme is associated with the synthesis of thyroid hormones?
thyroid peroxidase
- contains more than 120 tyrosine residues
- small fraction of iodinated tyrosines can be coupled together
thyroglobulin
How do the thyroid hormones T3 and T4 get released?
by the degradation of thyroglobulin in the lysosomes
How is serotonin made?
hydroxylation and decarboxylation of tryptophan
Enzyme: tryptophan hydroxylase
Co-factor: THBtn
Where is melatonin made?
pineal gland, released in dark cycle and induces sleepiness
What is niacin made from?
tryptophan
Enzyme: IDO (anti-cancer drug target)
The 3Ds and the ultimate D is associated with what disease? Due to what?
Pellagra - either due to lack of niacin or lack of tryptophan
(dermatitis, diarrhea, dementia, and death)
Decarboxylation of glutamate
GABA, requires B6
Decarboxylation of histidine
histamine, requires B6
- tripeptide with the sequence Glu-Cys-Gly
- the bond between Glu and Cys is not a peptide bond, but a gamma-glutamyl linkage, which is very resistant to proteolysis
- made in the liver
glutathione, the glutamyl linkage makes it a very stable molecule
What’s the function of glutathione?
intracellular reducing agent:
- scavenging free radicals
- destroying peroxides
- conjugate toxic molecules for excretion
In order to re-generate glutathione, glutathione reductase needs to use what reducing agent?
NADPH
How does G6PD deficiency affect glutathione regeneration?
NADPH is produced from G6PD in PPP
What will B6 deficiency affect?
- decarboxylation of glutamate (GABA) and histidine (histamine)
- serine hydroxymethyltransferase (serine»glycine)
- cystathione beta-synthase (homocysteine»cysteine)
- all aminotransferases
