Lecture 32 Flashcards
State the synthesis precursors (intermediate molecules) from the following pathways, that are used to synthesize AAs
Glycolysis: (3)
TCA Cycle: (2)
Pentose Phosphate Pathway: (2)
Glycolysis:
3-phosphoglycerate
PEP (Phosphoenol pyruvate)
Pyruvate
TCA Cycle:
Alpha-ketoglutarate
OAA
Pentose Phosphate Pathway:
Ribose-5-phosphate
Erythrose-5-phosphate
State the Essential AAs
Phenylalanine
Valine
Threonine
Tryptophan
Isoleucine
Methionine
Histidine
Arginine
Leucine
Lysine
("PVT TIM HALL" mnemonic)State the 3 Transamination reactions that occur via a pyridoxal phosphate-dependent (vitamine B12) reaction (enzyme, reactant, product)
- SGPT makes Pyruvate become Alanine
- SGOT makes OAA become Aspartate
- Glutamate Dehydrogenase makes Alpha-ketoglutarate become Glutamate
Once SGOT creates Aspartate from OAA, what 4 AA’s can it become and state the type of reactions it takes to create these
- Aspartate to Asparagine when Glutamine donates an NH3 group
- Aspartate to Lysine, Methionine, or Threonine (humans cannot conduct this reaction, therefore these AA’s are essential AAs)
Between Synthetases and Synthases, which uses ATP?
Synthetases
has an extra “T” bc it uses A”T”P
How is glutamine formed? why is it formed?
Glutamate has an NH3+ group put on it to form Glutamine
Glutamine is used to transport free NH4+ to the liver to eventually be excreted
Compare the Adenylation and Uridylylation in terms of their definitions. What does Adenylation inactivate?
Adenylation: the addition of an AMP ribonucleotide
Inactivates Glutamine Synthetase
Uridylylation: the addition of a UMP ribonucleotide
Describe what causes the feedback inhibition and feedforward activation that occurs in order to regulate the Uridylylation that PII conducts
Feedback Inhibition: Glutamine maintains PII in it’s inhibitory form (-UMP)
Feedforward Activation: Alpha-ketoglutarate + ATP maintain PII in its active form (+UMP)
Besides receiving another NH3+ group and becoming Glutamine, describe the other 2 possible “fates” of Glutamate. (include the type of reactions that carry out these fates)
- Forms Proline after several reductions and cyclizations
2. Forms Ornithine after 1 reduction and a transamination
Ornithine is ______ minus urea.
Arginine
What are the 3 AA derivatives of 3-Phosphoglycerate that can be formed?
- Serine
- Glycine (via removal of Serine’s side chain)
- Cysteine (via a homocysteine intermediated formed from Serine)
Tyrosine is a ______intermediate of ______. (catabolic or anabolic? ; AA for 2nd blank)
Catabolic
Phenylalanine
Aromatic AAs are synthesized from intermediates from what cellular pathway?
The Pentose Phosphate Pathway
Which aromatic AA is synthesized directly from Ribose-5-phosphate?
Histidine
State the 2 reactants that combine to form Chorismate. Also state the 3 possible aromatic AA’s that are formed using precursors from both the Pentose Phosphate Pathway and Glycolysis.
Erythrose-4-Phosphate + PEP = Chorismate
This forms Tryptophan, Phenylalanine, or Tyrosine
(this reactions occurs in plants/fungi NOT humans so these are essential AAs)
What 3 AA’s are synthesized from Pyruvate, exist ONLY to be incorporated into proteins, and have their synthesis regulated by feedback inhibition?
Valine, Leucine, and Isoleucine
“LIV” mnemonic ; the guys LIV to be part of proteins
State the 2 “Central AA’s”.
Glycine and Serine
Heme is a derivative of what AA? What conversion must occur prior to heme assemble?
Glycine
Acetate must be converted to Succinyl-CoA (prior to synthesizing heme)
Briefly describe what a Porphyria is. Compare the symptoms of a porphyria due to a liver enzyme issue and a Non-liver enzyme issue
Porphyria: Deficiency in heme synthesis
Liver Enzyme Deficiency (Porphyria): Pain and Cardiac Dysfunction
Kidney Enzyme Deficiency (Porphyria): Light sensitivity and Altered skin pigmentation
Explain why bruises change color over time
The Pie-Orbitals in the molecular structure of different substances absorb photons differently, giving off different colors
ex. Heme (purple) to Biliverdin (green) to Bilirubin (yellow) to
Stercobilin (brown) in feces
OR
Urobilin (yellow) in urine
Glutathione, Polyamines, and GABA are all derivatives of what AA? Briefly describe each of these
All derivatives of Glutamate
Glutathione: an antioxidant
Polyamines: Stabilize DNA (using their positive charges)
GABA: an inhibitory neurotransmitter
NO and Creatine Phosphate are both derivatives of what AA? Briefly describe both of these.
Arginine Derivatives
NO: a free radical that has 3 isozymes (cardiac signalling, Neuronal, and Immune cell)
Creatine Phosphate: a molecule created in the liver from Creatine that releases almost as much energy when hydrolyzed as the hydrolyzation of ATP
(uses a lot of SAM)
SAM is a derivative of what AA? what is the role of sam?
Methionine
SAM: primary methyl donor in cells
Histamine is a derivative of what AA? what does function does Histamine have in the body?
Histidine
Histamine is inflammatory, promotes secretion of HCl and Pepsin in the stomach, and is a neurotransmitter
