Biochem metabolism Flashcards
What are the regulators of phosphofructokinase 1 (PFK1)? (two +, two -)
+ AMP, fructose 2,6 bisphosphate
- ATP, citrate
What are the regulators of fructose 1,6-bisphosphatase? (two +, two -)
+ ATP, acetyl-CoA
- AMP fructose 2,6 bisphosphatase
What are the regulators of isocitrate dehydrogenase? (one +, 2 -)
+ ADP
- ATP, NADH
What is the enzyme needed to take glucose to G6P? Other way?
Hexokinase
Glucose-6-phosphatase
What is the enzyme needed to take G6P to fructose-6-phosphate?
GP isomerase
Where is Hexokinase found in highest quantities? Glucokinase?
Hexokinase = most tissues
Glucokinase = Liver and Beta cells of pancreas
What is the equation for Km, if K1 = rate from substrates to enzyme/substrate complex, K2 = rate from complex back to substrates, and K3 = rate from complex to products?
Km = (K2+K3)/K1
Which is induced by insulin, hexokinase, or glucokinase?
Hexokinase
Which is feedback inhibited by glucose, hexokinase or glucokinase?
hexokinase
Which has a gene mutation that is associated with maturity onset DM, hexokinase or glucokinase?
Glucokinase
What is the MOA or Arsenic?
Blocks ATP generation by phosphoglycerate kinase
What are the two downregulators of hexokinase?
G6P
Fructose-6-phosphate
What are the only two amino acids that are strictly ketogenic?
Lysine and Leucine
What are the findings of pyruvate dehydrogenase deficiency?
Neurological defects, lactic acidosis
What is the treatment for pyruvate dehydrogenase deficiency?
Increase ketogenic nutrients
What is the cofactor that is needed to keep glutathione reduced? What happens if this enzyme is impaired?
NADH
Hemolytic anemia
What is the enzyme that uses NADH to reduce glutathione? Oxidize it?
Glutathione reductase
Glutathione peroxidase
What is the cause of essential fructosuria? Symptoms?
Fructokinase does not function properly. Benign loss of fructose in urine.
What is the enzymatic cause of fructose intolerance?
Deficiency of aldolase B
What is the effect of galactokinase deficiency?
Galactouria, infantile cataracts,
What is the cause of classic galactosemia? Symptoms = ?
Absence of galactose-1-phosphate uridyltransferase
Symptoms = Infantile cataracts, MR, jaundice
What is the enzyme that converts glucose to sorbitol? Sorbitol to fructose?
Aldose reductase
Sorbitol dehydrogenase
Why is it that DM can damage the eye?
Eye only has aldose reductase, therefore there is an accumulation of sorbitol
Which type of aminoacids are needed, L or D?
L
What are the three amino acids that are only glucogenic?
M
V
H
What are the two acidic amino acids?
Aspartic acid
Glutamic acid
What are the three basic amino acids?
R
K
H
What are the substrates of the urea cycle? (hint: Ordinarily, careless crappers are frivolous about urination)?
Ornithine Carbamoyl phosphate Citrulline Argininosuccinate Fumarate Arginine Urea
Why is it that hyperammonemia leads to inhibition of the TCA cycle?
Loss of alpha-keto glutarate
What is the treatment for hyperammonemia? What are the two drugs that can be given?
Limit protein intake
Benzoate
Phenylbutyrate
What is the MOA of lactulose?
Acidify’s the Gi tract to trap NH4
What is the cause of n-acetylglutamate deficiency (what enzyme is affected)?
A required cofactor for carbamoyl phosphate synthetase I
What is the universal NH4 carrier?
Glutamate/ alpha ketoglutarate
What is ornithine transcarbamylase deficiency? Mode of inheritance? How is it diagnosed?
XLR loss of ornithine transcarbamylase
Orotic acid increased in the blood
What is the most common urea cycle disorder (which enzyme is deficient)?
ornithine transcarbamylase deficiency
What is the rxn that ornithine transcarbamylase catalyses”
Ornithine to citrulline
Orotic acid increased in the blood = ?
Ornithine transcarbamylase deficiency
What is the vitamin necessary to convert Y to niacin?
B6
What is the vitamin necessary to convert histidine to histamine?
B6
What is the enzyme necessary to convert E to GABA?
B6