Nitrogen/AAs Flashcards
10 Essential AAs
PVT TIM HALL Phenylalanine Valine Threonine Tryptophan Isoleucine Methionine Histidine (Arginine?) Leucine Lysine
2 Acidic and 3 Basic AAs
Aspartic acid and glutamic acid
Histidine, arginine, lysine
3 AAs as Components of Nuclear Localization Signal
Lysine, Arginine, Proline
7 Products from Phenylalanine Pathway (& enzymes/cofactors)
Phenylalanine to Tyrosine (phenylalanine dehydrogenase/BH4). Can be iodized to thyroxine
Tyrosine to Dopa (Tyrosine hydroxylase, BH4). Dopa can be converted to melanin, so a lot in substantia nigra. Lack can be albinism
Dopa to DA (Dopa decarboxylase/B6)
DA to NE (Vitamin C)
NE to Epi (SAM and Cortisol)
Carbidopa
Inhibits Dopa decarboxylase, so give with Levodopa to prevent peripheral breakdown
Degradation of DA/NE/Epi
Broken down by MAO and COMT to HVA, VMA, and Metanephrine respectively
Trp 4 Products (cofactors)
Trp to Niacin (B6) to NAD/NADP
Trp to 5HT (B4, B6) to Melatonin
Histidine Product (cofactor)
Histidine to histamine (B6)
Glycine Product(s) (cofactor)
Glycine to porphyrin (B6) to heme
Glutamate 2 Products (cofactor)
GABA (B6, so B6 deficiency get convulsions)
Glutathione
Arginine 3 Factors (cofactor)
Creatine
Urea
NO (BH4)
CPS I vs. CPS II (what it’s for, where it is, where it gets substrate)
For urea cycle vs. pyrimidine synthesis
mt vs. cytosol
ammonia vs. glutamine
Ornithine transcarbamylase Deficiency
Most common urea cycle enzyme deficiency. Get buildup of N and ammonia, presents in 1st few days. Low BUN
Hyperammonemia (2 causes, syndrome/symptoms, 4 treatments)
Liver disease or urea cycle enzyme deficiencies
Causes hepatoencephalopathy - tremor/slurring/somnolence/vomiting/edema/blurring of vision
Limit protein intake
Lactulose is main
Also benzoate and phenylbutyrate which bind AA for excretion
Lactulose Mech
Digested by bacteria to acidify GI tract, converting NH3 to NH4+ which can’t be absorbed and is thus excreted in colon
