Class 4: Amino Acid Metabolism Flashcards
What does amino acid output
- glucose + glycogen
- CO2 + H2O
- ketone bodies, fatty acids, steroids
2 ways Amino Acids Degrade
1) removal of the @-amino groups (nitrogen) by transamination and oxidative deamination
2) carbon skeletons of the @-ketoacids are converted to common intermediates of energy-producing, metabolic pathway
what’s the first step of degradation of amino acids
removing nitrogen
transamination
The transfer of the a-amino group of an amino acid to a-Keto acid
The end products: a-Keto acid and amino acid
enzyme: amino transferase
What is ALT transamination
alanine –> pyruvate
- predominantly in the liver, a more specific indicator of liver damage. (American Red Cross, hepatitis C)
what is AST transamination
aspartate –> oxaloacetate
- in the liver, heart (cardiac muscle), skeletal muscle, kidneys, brain, and red blood cells, damage to liver, muscle (creatine kinase), brain.
Oxidative Deamination
Place:
Enzyme:
Activators:
Inhibitors:
Coenzymes:
Place: liver and kidney
Enzyme: Glutamate dehydrogenase
Activators: ADP and GDP
Inhibitors: ATP and GTP (negative feedback regulation)
Coenzyme: NAD+ or NADP+
Oxidative Deamination
Place:
Enzyme:
Activators:
Inhibitors:
Coenzymes:
Place: liver and kidney
Enzyme: Glutamate dehydrogenase
Activators: ADP and GDP
Inhibitors: ATP and GTP (negative feedback regulation)
Coenzyme: NAD+ or NADP+
3 ways to transport and release ammonia
Transport:
a) As glutamine (to liver or kidney)
b) As alanine (to liver from muscle)
c) As urea (to kidney from liver)
Release:
- Urea (90%)
- ammonia ion (3%)
Urea cycle
aspartate + ammonium ( 2 nitrogen’s) –> 2 amines, neutral, non polar
1) The major disposal form of amino groups derived from amino acids
2) 90% of the nitrogen-containing components of urine
Where is the place of production and excretion of the urea cycle
Liver and Kidney
5 steps of Urea Cycle
1) Formation of carbamoyl phosphate (2 ATP)
2) Formation of citulline
3) Formation of Arginosuccinate
4) Cleavage of Argininosuccinate
5) Cleavage of arginine to ornithine and urea
5 steps of Urea Cycle
1) Formation of carbamoyl phosphate (2 ATP)
2) Formation of citulline
3) Formation of Arginosuccinate
4) Cleavage of Argininosuccinate
5) Cleavage of arginine to ornithine and urea
why is urea an irreversible process
4 high energy phosphates are consumed
find out more about the blood urea nitrogen test
BUN
what r the 2 fates of the carbo skeletons of amino acids
1) Amino Acids whose catabolism yields pyruvate or one of the intermediates of the TCA cycle can produce glucose - glucogenic
2) Amino Acids whose catabolism yields either acetoacetate or
acetyl CoA or acetoacetyl CoA - ketogenic
what amino acids form pyruvate
- serine
- cysteine
- alanine
- glycine
- threonine
- tryptophan
what is a FIGLU test:
a urine test, an indicator of Vitamin B12 or folic acid deficiency or liver disease
FIGLU: N-Formiminoglutamate
what is a FIGLU test:
a urine test, an indicator of Vitamin B12 or folic acid deficiency or liver disease
FIGLU: N-Formiminoglutamate
what amino acids form fumarate
phenylalanine
tyrosine
what is PKU
- deficiency of phylalanine hydroxylase
- Hyperphenylalaninemia
- Defect in the conversion of Phenylalanine to Tyrosine
wha is “mousy”
odor in urine
CNS Symptoms
-Cognitive disability or intellectual disability
-Cerebral and basal ganglion dysfunction)
-failure to walk or talk
-seizure and failure to grow
CNS potential causes
1) lack of the tyrosine, precursor of catecholamines (norepinephrine)
2) toxic effect of high levels of phenylalanine in the brain, blocking the transport or metabolism of other aromatic amino acids (e.g., tyrosine, tryptophan)
3) Inhibit the synthesis of other substances required for brain growth (Microcephaly)
4) Hypopigmentation: fair hair, light skin color and blue eyes, no melanin (Albinism)
