Ford (Amino Acid Synthesis) Flashcards
Synthesis of AA from 3 pathways intermediates
- Glycolysis: 3-phosphoglycerate, phosphoenolpyruvate, pyruvate
- TCA Cycle: a-ketoglutarate, oxaloacetate
- Pentose Phosphate Pathway: ribose-5-phosphate, erythrose-4-phosphate
Nonessential Amino Acids
- alanine
- asparagine
- aspartic acid
- cysteine
- glutamic acid
- glutamine
- glycine
- proline
- serine
- tyrosine
Essential Amino Acids (PVT TIM HALL)
- histidine
- isoleucine
- leucine
- lysine
- phenylalanine
- threonine
- tryptophan
- valine
- arginine
- methionine
- tend to be SECONDARY syntheses
Amino Acid Syntheses - Transamination Reactions
- Pyruvate –> Alanine (SGPT)
- OAA –> Aspartate (SGOT)
- a-ketoglutarate –> glutamate (glutamate dehydrogenase)
Amino Acid Syntheses - Aspartate Fates
- glutamine donates NH3 to aspartate –> asparagine
- aspartate modified –> lysine, methionine, threonine
- tightly regulated by feedback inhibition
Amino Acid Syntheses - Glutamate Fates
glutamate –> glutamine (transport free NH4 to liver)
Synthetases use ATP, Synthases do NOT use ATP
- reduction/cyclization = PROLINE
- reducation/transamination = ORNITHINE
- arginine minus urea*
Glutamine Synthesis Regulation
- adenylation INACTIVATES Glutamine Synthetase
- addition of AMP ribonucleotide
- uridylylation ACTIVATES Glutamine Synthetase
- addition of UMP ribonucleotide
Glutamine = UMP (-) --> inhibitory a-ketoglutarate/ATP = UMP (+) --> activating
Heme
- glycine derivative
- make heme to facilitate oxygen transport
- main source of dietary iron
Porphyrias
- deficiencies in Heme Synthesis
Liver enzyme: pain and cardiac dysfunction
Non-liver enzyme: light-sensitivity, altered skin pigmentation
Glutamate-Derived Molecules (3)
- Glutathione = antioxidant
- Polyamines = stabilize DNA
- GABA = inhibitory neurotransmitter (Glutamate = excitatory neurotransmitter)
Arginine-Derived Molecules (2)
- NO = free radical
- Nitric Oxide Synthase
- G-protein signaling cascade
- Creatine Phosphate
- hydrolysis of phosphate releases just as much free energy as ATP hydrolysis
- creatinine excreted in urine
- creatine synth uses more SAM than all methylation rxns combined
Methionine-Derived Molecules
SAM –> primary methyl donor in cells
Histidine-Derived Molecules
- decarboxylated with pyridoxal phosphate = HISTAMINE
- promotes HCl/Pepsin secretion in stomach
- vasodilator at trauma rxn site
- neurotransmitter
Antihistamines = competitive inhibitors
Tryptophan-Derived Molecules
serotonin
- precursor for melatonin (light-dark cycle regulator)
- vasoconstrictor
- intestine contract around food
- activate NOS/regulate bone mass
Tyrosine-Derived Molecules
- Epinephrine: adrenaline
- stress hormone
- Norepinephrine = neurotransmitter
- vascular constriction, inc. blood pressure, ceasing inflammation
- Dopamine
- signaling abnormalities are hallmarks of Parkinsons, Schizophrenia, drug addiction, ADHD