Synthesis of Amino Acids Flashcards
Which amino acids can bacteria and plants synthesize?
All the amino acids
Which amino acids can mammals synthesize?
Only synthesize 10 amino acids from intermediates of metabolic pathways due to a lack of enzymatic machinery
Are all intermediates a source of an amino group?
- NO; most only have a carbon backbone
- Glutamate and Glutamine are the sources of the amino group
What is the mnemonic for the essential amino acids?
Vegetarian Prescribed High Lipid Meal To Increase Triglyceride Levels
What are the 9 essential amino acids?
Valine Phenylalanine Histidine Methionine Threonine Isoleucine Tryptophan Leucine
What are non-standard amino acids termed? Provide examples.
- Non-protein coding amino acids
- Ex: GABA, homocysteine, man-made amino acids
What is the 21st amino acids? What is it derived from? Where can it be synthesized?
- Selenocysteine
- Formed from selenium
- Synthesized on tRNA from cysteine
Selenocysteine is coded by what? In what types of situations?
- UGA in a context-depending manner
- UGA does not ALWAYS code for selenocysteine (it is normally a stop-codon)
What is the 22nd amino acid? In what organisms is it utilized in?
- Pyrrolysine
- Utilized in methane-producing bacteria
- NOT utilized in mammals or Eukaryotes
What is tyrosine derived from?
- Phenylalanine (essential)
- Tyrosine (conditionally essential)
What can a-ketoglutarate synthesize?
Glutamate
What can glutamate synthesize?
- Glutamine
- Proline
- Arginine
Why are glutamine, proline, and arginine conditionally essential?
The enzymatic machinery that converts glutamate to theses AA may not be efficient in certain situations
3-phosphoglycerate is an intermediate of what?
Glycolysis
What can 3-phosphoglycerate synthesize?
Serine
What can serine synthesize?
- Glycine (conditionally essential)
- Cysteine (conditionally essential)
What can oxaloacetate synthesize?
Aspartate
What can aspartate synthesize?
- Asparagine
- Methionine
- Lysine
- Threonine
Why is asparagine a special amino acid?
- For reasons unknown, certain malignant lymphocytes require Asparagine for growth
- Enzymes involved in the synthesis of Asparagine from Aspartate are targeted for cancer therapy
Is asparagine essential, non-essential, or conditionally essential?
Conditionally essential
Is alanine essential, non-essential, or conditionally essential?
Non-essential
What can pyruvate synthesize?
- Alanine
- Valine
- Leucine
- Isoleucine
In what organisms may phenylalanine be synthesized to produce tyrosine?
In mammals alone
What produces phenylalanine, tyrosine, and tryptophan?
Phosphoenolpyruvate + erythrose 4-phosphate
What can ribose-5-phosphate synthesize?
Histidine
Is the pentose phosphate pathway important for amino acid synthesis in mammals? Why/why not?
- Not important
- Since histidine is an essential amino acid
What is the consequence of an accumulation of porphyrin intermediates?
Porphyria diseases
What are the two steps to heme synthesis?
1) Glycine interacts with Succinyl-CoA
2) Delta-Aminolevulinate (8) are combined and hydrated
Plants and most bacteria synthesize Delta-Aminolevulinate from what?
Glutamate
What does glycine need to interact with to produce Delta-Aminolevulinate?
Succinyl-CoA
How many Delta-Aminolevulinate must be combined in heme synthesis?
8
The combination of 8 Delta-Aminolevulinate and hydration results in what?
Porphobilinogen, creating the first benzene ring structure
How is protoporphryin created? What must be incorporated to produce heme?
- Through the addition of ring structures to porphobilinogen
- When protoporphryin incorporates iron = heme
What acts as a precursor for bile pigments through bile acid synthesis?
Heme
What does heme oxygenase do?
- Removes CO and Fe3+ from heme
- Converts heme to biliverdin
What does biliverdin reductase do?
Reduces biliverdin to produce bilirubin
Where is bilirubin transported to? What is it bound to?
Bilirubin is transported in the blood with serum albumin into the liver
What does Glucoronyl-bilirubin transferase do?
Converts bilirubin to bilirubin diglucoronide, which is secreted in the intestine
What happens bilirubin diglucoronide in the intestine?
Bacteria converts it to urobilinogen
What are the two possible pathways of urobilinogen?
- Transported to the kidney and converted to urobilin (excreted)
- Converted to stercobilin in the intestine (excreted)
What happens when someone gets a bruise?
- When heme escapes, it loses oxygen and appears purple-black
- Hours: heme is converted to biliverdin (green)
- Days: bilirubin (yellow)
What is the consequence of an accumulation of bilirubin?
Jaundice (infants)
Which amino acids is creatine derived from?
- Glycine
- Arginine
- Methionine
How does creatine become phosphocreatine?
Phosphorylated by creatine kinase
What is the function of phosphocreatine?
- Stores phosphate groups for ATP synthesis
- Buffer system for muscular ATP
What did Dr. Lucy Willis do in the Serendipity Leukemia treatment?
- Folate treatment for macrolytic anemia
- India
What did Dr. Y Subbarao do in the Serendipity Leukemia treatment?
- Purified creatine and ATP
- Methotrexate
What did Dr. Sidney Farbey do in the Serendipity Leukemia treatment?
- Methotrexate treatment for leukemia
- “Anti-folate”
What is glutathione synthesized from?
- Glutamate
- Cysteine
- Glycine
What is the function of glutathione?
Prevents oxidative damage
What is epinephrine derived from? What is its function?
- Tyrosine
- Fight or flight
What is GABA derived from? What is its function?
- Glutamate
- Main inhibitory signal in the CNS
- Needed for muscle tone
What is histamine derived from? What is its function?
- Histidine
- Released during allergic reactions
- Stimulates HCl secretion in the stomach
What is serotonin derived from? What is its function?
- Tryptophan
- Regulates intestinal movement
- “Feel-good” hormone
