Term
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Definition
| Ammonia is highly toxic to the CNS at concentrations above |
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Term
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Definition
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Term
1. Transaminase
2. glutamate dehydrogenase |
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Definition
| permits a-ketoglutarate to collect nitrogen from other amino acids and then release amoonia for urea synthesis |
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Term
1. Transamination and Glutamate dehydrogenase
2. Serine/threonine dehydratase
3. Amino acid oxidases(minor)
4. indirect deamination - the purine nucleotide cycle |
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Definition
| 4 Pathways for amino acid deamination |
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Term
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Definition
| removal of the amide nitrogen groups ivolves deamidation rather than deamination |
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Term
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Definition
| in the Purine Nucleotide Cycle, this removes NH4 from AMP to make IMP |
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Term
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Definition
| provides the amino group for IMP to be converted back to AMP |
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Term
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Definition
| irreversible, there is a separate glutamine synthetase |
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Term
1.Glutamate dehydrogenase
2.Serine/Threonine dehydratase and histidine deaminase
3. the purine nucleotide cycle
4. deamidation
5. bacterial nitrogen |
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Definition
| 5 sources of NH4 for the urea cycle |
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Term
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Definition
| Amino groups are transported to the liver from other tissues primarily as |
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Term
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Definition
| also provides nitrogen for aspartate synthesis |
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Term
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Definition
| Urea is synthesized on amino acid intermediates starting with |
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Term
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Definition
| cleavage of urea from arginine regenerates |
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Term
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Definition
| first two reactions of the urea cycle are located in the |
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Term
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Definition
| last three reactions of the Urea cycle are in the |
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Term
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Definition
| first two reactions of the urea cycle are located in the |
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Term
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Definition
| hydrolysis of arginine that makes urea and ornitine |
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Term
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Definition
| an a-amino acid that is not used for protein synthesis |
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Term
| CPS1 (carbamoyl phosphate synthase I) |
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Definition
| initial step in urea cycle, CO2 + NH4 + 2ATP --> carbamoyl phosphate, mitochondrial |
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Term
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Definition
| is cytosolic and generates carbamoyl phosphate for pyrimidine biosynthesis |
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Term
| Ornithine transcarbamoylase (OTC) |
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Definition
| catalyzes the transfer of the carbamyl group from carbamyl phosphate to ornitine |
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Term
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Definition
| Product of ornitine transcarbamoylase |
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Term
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Definition
| gene is located on the X chromosome, thus are X linked |
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Term
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Definition
| 3rd reaction of urea cycle that utilizes citrulline and aspartate and ATP (utilizes 2 P bonds) to produce argininosuccinate |
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Term
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Definition
| cleaves arginosuccinate to produce fumarate and arginine |
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Term
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Definition
| splits off urea and regenerates ornitine |
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Term
| antiport in mitochondrial membrane orn-in cit-out |
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Definition
| transport of citrulline and ornithine |
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Term
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Definition
| can enter the TCA cycle to form oxaloacetate |
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Term
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Definition
| The TCA enzyme that produces OAA from malate |
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Term
| transamination to aspartate |
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Definition
| OAA can undergo gluconeogenesis or undergo... and can re-enter the the urea cycle |
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Term
| in cytosol and mitochondria |
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Definition
| fumarase, malate dehydrogenase, and aspartate are located |
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Term
1. feed foward - substrate availibilty
2. allosteric regulation of carbamoyl phosphate synthesis
3. increase transcription of urea cycle enzymes |
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Definition
| three types of regulation on the Urea cycle |
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Term
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Definition
| activates CPS1, has a regulatory role but is not a normal metabolic intermediate, synthesis is stimulated by arginine |
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Term
| N-Acetylglutamate synthase |
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Definition
| Uses Acetyl-CoA and Gutamate to produce N-Acetylglutamate |
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Term
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Definition
| causes hyperammonemia in adults |
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Term
| immature liver function and/or hepatic blood flow |
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Definition
| causes hyperammonemia in neonates |
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Term
| Urea cycle enzymes or ornitine translocase deficiency |
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Definition
| genetic causes of hyperammonemia |
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Term
| shifting a-ketoglutarate to glutamate |
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Definition
| High NH3 can deplete the TCA cycle by |
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Term
|
Definition
| hyperammonemia is usually accompanied by increased plasma |
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Term
| hemodialysis and peritoneal dialysis |
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Definition
| ways to remove excess ammonia |
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Term
| restrict dietary protein, antibiotics to decrease gut bacterial NH4 synthesis |
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Definition
| ways to decrease ammonia synthesis |
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Term
| benzoate and phenylbutyrate |
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Definition
| drugs that provide alternate pathways for nitrogen excretion |
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Term
|
Definition
| an odorless precursor of phenylacetate |
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Term
| Ornithine Transcarbamoylase deficiency |
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Definition
| most common genetic defect of urea cycle, hyperammonemia and metabolic alkalosis, low BUN, hypergluataminemia, orotic aciduria |
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Term
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Definition
| symptom unique to OTC deficiency |
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Term
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Definition
| becomes an essential amino acid in individuals with urea cycle deficiencies |
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Term
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Definition
| causes an increased accumulation of mitochondrial carbamoyl phosphate that can spill out into the cytosol |
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Term
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Definition
| the spilling out of carbamoyl phosphate bypasses the first regulated step of pyrimidine synthesis and results in and increased synthesis of |
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Term
|
Definition
| Nucleotide synthesis, Source of N is glutamine, is located in the cytosol, activated by PRPP and inhibited by UTP |
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Term
|
Definition
| a key intermediated in purine and pyrimidine biosynthesis |
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Term
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Definition
| adults with partial defects in urea synthesis |
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Term
| Lysinuric protein intolerance |
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Definition
| rare, defective transporter for dibasic amino acids, lysine, ornithine, and arginine in urine, lack of ornithine for OTC activity, treat with oral citrulline |
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Term
|
Definition
| indicative of impaired renal function, poor renal perfusion or severe dehydration |
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Term
| increased excretion of ammonium ions |
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Definition
| accompanies excreation of organic acids, starvation, poorly regulated type I diabetes, many inborn errors of metabolism |
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