Amino Acids Flashcards
Form of amino acids that are found in proteins
L form
Essential amino acids groups
- Glucogenic
- Glucogenic/ketogenic
- Ketogenic
All…..amino acids need to be supplied in the diet
Essential
A ketogenic amino acid is an amino acid that….
can be degraded directly into acetyl CoA through ketogenesis
Essential glucogenic amino acids
- Methionine (Met)
- Valine (Val)
- Histidine (His)
Glucogenic amino acid is an amino acid that…..
Can be converted into glucose through gluconeogenesis
Essential ketogenic amino acids
- Leucine (Leu)
2. Lysine (Lys)
Essential glucogenic/ketogenic amino acids
- Isoleucine (ile)
- Phenylalanine
- Threonine
- Tryptophan
Acidic amino acids and charge
Aspartic acid (Asp) Glutamic acid (Glu) both negative
Basic amino acids and charge
Arginine (Arg) - positive
Lysine (lys) - positive
Histidine (his) - no charge
Amino acids required during periods of growth
Arginine
Histidine
The most basic amino acid
Arginine
Amino acids of histones
Arginine
Lysine
Amino acid catabolism result in the formation of
Common metabolites (pyruvate, acetyl CoA e.g.), which serves as metabolic fluids
Amino acid catabolism result in excess
Nitrogen (NH3)
Nitrogen is converted to
Urea and excreted by the kidneys
Urea cycle - reactions and locations
- CO2 + NH3 + 2ATP –> carbamoyl phosphate + 2ADP + P ( carbamoyl phosphate synthase 1 and N-acetygkutamate as a cofactor) (Mitochondria)
- Carbamoyl phosphate + ornithine –> citrulline Ornithine transcarbamylase) (Mitochondria)
- Citruline + aspartate + ATP–> AMP + PPi + Argininosuccinate (arginossuccinate synthetase)
Cytoplasm - Argininosuccinate –> arginine and fumarate (arginosuccinase) Cytoplasm
- arginine + H20 –> UREA + Ornithine (Arginase) cytoplasm
Urea productuon reaction
Location
Arginine + H2O –> ornithine + Urea
Enzyme arginase
Location:cytoplasm of liver
Urea production location
Cytoplasm of liver
Location of ornithine transcarbamylase action
Mitochondria of the liver
Ornithine transcarbamylase reaction
Location
Carbamoyl phosphate + ornithine –> citrulline
Mitochondria
Arginosuccinate: next step
To arginine and fumarate (arginosuccinase)
Urea structure
NH2 (NH3) | C=O (CO2) | NH2 (aspartate)
Arginosuccinate: next step
To arginine and fumarate (arginosuccinase)
Urea is excreted by
Kidney
Urea cycle site
Both Mitochondria and cytoplasm of the liver
Enzyme responsible for urea production
Arginase
Aminoacids(NH3) to a-ketoacids causes
A ketoglutarate to glutamate(NH3)
Glutamate(NH3) to a-ketoglutorate causes
Pyruvate to alanine (NH3)
Cori cycle
Glucose to pyruvate to lactate (muscle)
Lactate to pyruvate to glucose (liver)
Glucose back to muscle
Alanine cycle (cahill cycle)
Pyruvate-alanine (muscle)
Alanine(NH3) to pyruvate (liver) converting a-ketoglutorate to glutamate(NH3)
pyruvate to glucose (liver)
Liver back to muscle
Hyperammonemia can be divided to
- Acquired (liver disease)
2. Hereditary (urea cycle enzyme deficiencies
Transport of ammonia by
Alanine and glutamate
Hyperammonemia results in
Excess NH4+
Excess NH4+ in hyperammonemia results in
a-ketoglutarate depletion, leading to inhibition of TCA cycle
Carbamoyl phosphate synthetase I cofactor
N-acteylglutammate
Hyperammonemia treatment
- Limit protein diet
- Phenylbutyrate or Benzoate (bind aminoacid and lead to excretion) may be given to decrease ammonia levels
- Lactulose to acidify the GI tract and trap NH4+ for exertion
- Rifamixin to decrease colonic ammoniagenic bacteria
N-acetyglutamate deficiency leads to
Hyperammonemia
N-acetyglutamate deficiency is identical to
Carbamoyl synthetase I deficiency
Ornithine trancarbamylase deficiency mode of inheritance
XR (vs other urea cycle enzyme deficiency which are autosomal recessive)
Lab findings that suggest N-acetyglutamate deficiency and clinical presentation
Increased ornithine with normal urea cycle enzymes
- poorly regulated respiration and body Q
- poor feeding
- developmental delay
- intellectual disability
Most common urea cycle disorder
Ornithine trancarbamylase deficiency
Urea cycle enzymes deficiencies are AR except
Ornithine trancarbamylase deficiency –> XR
Ornithine trancarbamylase deficiency / pathophysiology
Interferes with the body’s ability to eliminate ammonia
Ornithine trancarbamylase deficiency/ often evident in (age)
First few days of live, but may present with late onset
Ornithine trancarbamylase deficiency /what is happening with the excess carbamoyl phosphate
Is converted to orotic acid
Ornithine trancarbamylase deficiency findings
- Increased orotic acid blood and urine
- Decreased BUN
- Symptoms of hyperammonemia
- NO MEGALOBLASTIC ANEMIA (vs orotic aciduria)
Orotic aciduria vs Ornithine trancarbamylase deficiency (lab)
Ornithine trancarbamylase deficiency has no megaloblastic anemia