Random-ass MBOD Flashcards
Name the 2 ketogenic AA’s
Leu, Lys
Name the amino acids that are both keto and glycogenic?
Phe
Tyr
Trp
Ile
The body doesn’t store AA’s. Where does it put them then?
Muscle protein
When you are not ingesting food, the body still maintains a normal concentration of free AA’s in the blood. Where do these AA’s come from?
THe breakdown of muscle proteins.
In order to use free AA’s, what must be done first? What problem results?
Deamination of free AA’s must occur before the body can use them. This creates a buildup of nitrogenous waste in the blood.
What effect do glucocorticoids and thyroid hormones have on the breakdown of proteins>
They increase protein breakdown.
REMEMBER: Insulin is the ANABOLIC hormone. Glucagon is CATABOLIC
Yeah.
Name some proteins with high turnover rates:
Heme, muscle protein, digestive enzymes
What AA is only essential during development and growth, but nonessential in adulthood?
Arginine
What non-essential AA is derives from Phe?
Tyr
WHat nonessential AA is derives from Met?
Cys
How many essential AA’s are there? Name them.
- PVT TIM HALL
Phe Val Thr Trp Ile Met His Lys Leu
The majority of protein degradation that takes place in the body is of endogenous protein or dietary protein?
Endogenous.
Dietary protein is broken down and used for synths of new proteins.
Dx this:
- muscle wasting
- decreased albumin levels
- distended abdomen
- child
- non-varied diet
Kwashiorkor- the absence of dietary essential amino acids
No ability to synthesize pancreatic enzymes and new intestinal cells.
HOw would you treat Kwashiorkor?
Add Pancreatic protease to the diet
In muscle, as proteins are broken down, they are trans/deaminated. What AA does the muscle export and what is its purpose?
NH3 from all the other AA’s in muscle are funneled to ALANINE for transport to the liver. Rids the muscle of excess nitrogenous waste.
Name the 3 ways AA’s are transported.
Na+ dependent carriers
Facilitated Transporter
Gamma - glutamyl cycle
What tissues use the gamma-glutamyl cycle for AA import?
Intestine and Kidney
What substance is necessary for the gamma-glutamyl cycle to work?
GSH - Glutathione
What 2 diseases of AA transport defects produce hyperaminoacidUREA?
Hartnup Disease (Neutral AA Urea)
Cystinuria
What’s the main treatment for Hartnup Disease (Neutral Amino Acid Urea)
Niacin and HIGH protein diet
What is the defect in Hartnup disease>
The intestine and kidney can’t absorb NEUTRAL and AROMATIC AA’s.
Remember: BOTH INTESTINE AND KIDNEYS INVOLVED
What essential substance is deficient if a person has Hartnup disease?
No tryptophan (essential AA), so no NIACIN, which is necessary for Nad+/ NADH
What is the defect involved with Cystinuria?
KIDNEY ONLY: Kidney can’t absorb cysteine and basic amino acids
Cystine and basic AA’s lost in the urine
Do you have an AA deficiency in Cystinuria?
No. Cysteine and basic AA’s are non-essential so no deficiency will be noted.
What is the worst symptom of Cystinuria?
Due to increased amount of Cysteine in the urine, kidney stones form. Cysteine is INSOLUBLE in urine.
What are the 2 substances that can cause kidney stones (that we have learned about)?
Cystine and Oxalate ?
How do you treat Cystinuria?
Goal is to increase Cystine solubility.
- Maintain large urine volume
- Neutral or basic pH of urine
- PENICILLAMINE (increases solubility of cystine)
Do patients with Hartnup (Neutral AA Urea) or Cystinurea have hyperaminoacidemia?
No
What are the 2 ways to remove alpha amino groups from an amino acid?
Transamination (most common) and deamination
The a-ketoacid of Alanine is……
Pyruvate
The a-ketoacid of Aspartate is……
Oxaloacetate
What is the only amino acid that can enter the Urea cycle? (Hint: it donates an NH3 to urea)
Aspartate
The a-ketoacid of glutamate is …..
a-ketoglutarate
Name the 2 most important transaminases.
(ALT) Alanine Amino-transferase
(AST)Aspartate Amino-transferase
Presence of both ALT and AST in serum is indicative of…..
Liver damage
Where will you find the ALT enzyme?
IN the mitochondria of liver and cytosol of muscle
WHere will you find the AST enzyme?
Only in the liver
Aminotransferase enzymes require what cofactor?
PLP - Piroxidal 5” Phosphate
Once the aminotransferases have created glutamate, what deaminase removes the NH3 from it?
Glutamate Dehydrogenase -> a-ketoglutarate + NH3 + NADPH
What effect does Vitamin B deficiency have on transaminase reactions?
Inhibits. Need Vit B6 to synthesize PLP, which is necessary for transaminase activity.
Some AA’s are specifically deaminated by certain enzymes. Asn and Gln are examples. What are they deaminated by?
Asparaginase and Glutaminase to form Aspartate and Glutamate, which are then deaminated by ALT in liver, and glutamate dehydrogenase.
Serine and Threonine are directly de-aminated by _____, which requires ______ to function.
Ser and The Dehydrogenase- PLP dependent!
At physiological pH, what form is nitrogen in? (NH3, NH4+)
Which form can cross cell membranes and into kidney tubules?
NH4+ is most common at physiological pH
NH3 is able to be secreted
How does ammonia regulate the pH of urine?
It is secreted into the kidney tubules as NH3. ONce in the urine, it binds free H+ atoms to form NH4+. This form can no longer cross the membrane
What species within the era cycle carry the 2 nitrogens to donate to urea?
Citruline and Aspartate
Carbamoyl Phosphate uses what enzyme?
CPS1 (carbamoyl -Pi synthase 1)
CPS1 relies on what coenzyme?
NAG / NAG synthase
Deficiency in NAG, NAGS, or CPS1 causes what?
Type 1 Hyperammonemia - Urea cycle shuts down
How do you cure type 1 hyperammonemia?
Benzoate and Phenylacetate to rid the blood of Glu and Gln. The body is then forced to use the excess NH4+ for essential AA synthesis.
How do you diagnose an OTC deficiency?
OTC is Ornithine transcarbamylase, which catalyzes the formation of citrulline. So no citruline, and OROTIC ACID is present.
What other pathway is orotic acid involved in?
Pyrimidine synthesis. So turn urea cycle off, turn on pyrimidine synthesis.
How does excess urea affect the brain?
The body stores excess NH4+ as Glu and Gln. The order goes a-ketoglutarate to glutamate, to glutamine. Eventually, all the glutamate is used up and a-ketoglutarate is used to form more. This depletes the TCA cycle= cell death.
Also, no more glutamate = no more GABA
Increased osmotic pressure = edema
Mutations in both CPS1 and OTC cause…..
Hyperammonemia, which can be treated with benzoate and phenyl acetate.
Arginosuccinase deficiency can be partially bypassed by:
- Restricting protein intake
- ARGININE SUPPLEMENTS
