Flashcards in Tough ones Deck (82):
Where does Q get it's ammonium from?
What is the role of ALT in starvation?
Takes pyruvate generated in muscles and converts it to alanine for transport to the liver
N (when produced from Q) gets it NH4 from where?
What is the enzyme that catalyzes the reaction of glycine to serine?
What is the most oxidized form of THF?
What is the most reduced form of THF?
What are the molecule that donate to the one carbon pool?
Formaldehyde, formate, S, G, H
What is the cause and symptoms of Homocystieneuria?
Defect in Cystathinoine beta synthase
Lens dislocation, MR, thromboembolism
What are the symptoms of PKU? Treatment?
MR, SZs, rash
Low F and Y diet
Which amino acids serve as carbon donors in the blood?
A and Q
HHF6 lowers the activity of what other enzyme? What is this involved in?
N-acetyl glutaminase, which lower the N-acetyl Q production an the urea cycle.
A defect in the glycine cleavage system will result in what condition?
Biotin is needed for what reaction?
Propionyl-coa to d-methylmalonyl-coa via propionyl coa decarboxylase
There are only two reactions in the body that require B12. Which are they?
Propionyl to succinyl-coa reaction
Homocystine to methionine reaction
The ONLY reaction in the body that can oxidize N5-methyl THF is what reaction? What variant of THF is produced in the process?
What is the chemical responsible for he discoloration of alkaptonuria?
Tyrosenemia I is the result of a defect in fumarylacetoacetate hydrolase. What is produced INSTEAD of fumarate and acetate?
Which amino acids can undergo deamination without an aminotransferase?
In the intestinal renal axis, what amino acid is picked up? What is it then converted to?
Q, then citrulline, then R
There are two compounds given to someone with urea cycle issues. Name them, and the amino acids they reaction with.
Phenyl-butryrate reactions with glutamine
Benzoate reacts with glycine
Name the enzyme that produces GABA from E, and Histamine from H
FA oxidation/ketone synthesis increases transcription for related enzymes through what system?
Gluconeogenesis stimulate transription of enzymes through what?
Insulin induces transcription of lipid synthesis enzymes via what?
Insulin represses transcription of gluconeogenesis enzymes via what?
The enzyme IDO converts what to what in which pathway?
W to N-formylynurine in the synthesis of niacin
How does the enzyme IDO contribute to cancer?
Excess activity leads to the blocking of T cell action on cancer cells
A defect in carbomoyl synthetase I leads to what condition?
A defect in Ornathine transcarbamoylase leads to what condition?
A defect in arginosuccinate synthetase leads to what condition?
A defect in Arginosuccinate lyase leads to what condition?
Arginosuccinate acid uria
A defect in Arginase leads to what condition?
What enzyme catalyzes the transfer of Glutathione to chemicals for breakdown?
What are three symptoms common to DM patients?
Gluconeogenesis from muscles
Why is there hyperlipidemia in DM patients?
Insulin is either ineffective at inhibiting HSL or not present.
What are the two main transcription changes brought about by insulin?
Increases in FA synthetase
Decrease in PEP carboxykinase
AIP is the result of a defect in what enzyme? What are the symptoms?
Defect in PBG deamidase. Acute abdominal pain, dark red urine, and neuro symptoms
PCT is the result of a defect in which enzyme? Symptoms?
UPG III decarboxylase.
Photosensitivity, pink urine
What enzymes in the heme cycle does Pb inhibit?
ALA synthase and Ferrochelatase
What gives urine and stool their characteristic color?
How will PREhepatic jaundice present in regards to bilirubin in the serum, urine, and stool?
Elevated unconjugated bili in blood
No change in urine or stool
How will HEPATIC jaundice present in regards to bilirubin in the serum, urine, and stool?
Increase is unconjugated bili in the blood
Lower amount of bili in urine and stool
How will POSThepatic jaundice present in regards to bilirubin in the serum, urine, and stool?
Increase in conjugated bili in the blood
Stool bili lower
Urine bili way higher
PRPP is synthesized from what substrate and via which enzyme?
What is the enzyme that comitted PRPP to purine synthesis? What is the product?
What are the four components that the purine de-novo synthesis pathway require?
Amino acids (GED)
N10 formyl THF
What is required for AMP synthesis? For GMP?
GTP and ATP respectively.
AMP and GMP are phosphorylated by what enzymes?
nucleotide mono(di)phosphate kinases
PRPP synthetase in inhibited by what?
ADP and GDP
What are the inhibitors and activators of Amidoribosyl transferase?
Inhibitors = GMP, AMP,
Activator = PRPP
Why does EtOH consumption worsen symptoms of gout?
Liver damage = increased ATP turnover, lactic acid production competes with uric acid for excretion
What is the treatment for gout? What does the chemical used get metabolized into?
Ortic acid uria is the result of a defect in what enzyme?
UMP synthase is a combination of which two enzymes?
Oratate phosphoribosyl transferase and OMP decarboxylase
CAD is a combination of which three enzymes?
Carbamoyl phophate sythetase
Megaloblastic anemia that responds to Folate and B12 is the result of what? If these do not produce a response, then what is responsible?
B12 deficiency (acts on Homocysteine to methionine rxn and THF generation--no purines)
Ortic acid uria if not responsive (no pyrimidine synthesis due to UMP synthase defect).
Hydroxyurea blocks which reaction?
Deoxyribonucleotides are producted via which enzyme?
Ribonucleotide reductase requires what molecule to reduce ribonucleotide?
Thioredoxin is reduced back from it oxidative state via which enzyme? Which electron donor molecule does this require?
Which dNTP regulates all dNTP production
How is CTP generated?
From UTP via CTP synthase
SCID is a defect in what enzyme?
A defect in adenosine deaminase results in the accumulation of adenosine in the degradation of AMP. What disease does this result in?
True or false: CMP, TMP, UMP are all phosphorylated by mono(di)ribonucletoide phosphate kinases to produced CTP, TTP and UTP.
TMP, TDP, and TTP do no exist in the body--only dTMP
5-fluorouracil is converted into what, then what, and inhibits what?
FUMP, FdUMP, and irreversibly binds Thymidylate synthase
Beta-alanine is produced from what?
Degradation of the pyrimidines UMP, CMP, and dCMP
Betaisobutryate is produced from what?
Degradation of the pyrimidine dTMP
(used as a measure of DNA turnover)
Purine bases (guanine, hypoxanthine, and adenine) are converted to their nucleosides by which enzymes?
Hypoxanthine-guanine phosphoribosyltransferase (HGPRTase)
Adenine phosphoribosyltransferase (APRTase)
APRTase is inhibited by what?
Inhibited by AMT
HGPRTase is inhibited by what?
Inhibited by GMP, IMP
There is only one purine NUCLEOTIDE that can be taken up. Which is it?
Adenosine by adenosine kinase
Which pyrimidine BASE cannot be taken up by humans?
Lesch-Nyhan syndrome is the result of a defect in what enzyme? Symptoms?
Symptoms - hyperuriemia, MR, chewing off of fingers
Free pyrimidines (not cytosine) are taken up by which enzyme?
What enzyme in fungi allows for the use of 5-fluorocytosine as a antifungal medication?
Methotrexate is an inhibitor of what enzyme? How does this affect DNA synthesis?
Inhibits dihydrofolate reductase, part of the thymidylate synthase reaction. Thus dTMP cannot be produced.
Carbamoyl phosphate synthase II is regulated by what?
Activated by PRPP
Inhibited by UMP
CTP synthase is regulated by what?
Activated by UTP
Inhibited by CTP
Where does CTP synthase get amine group from?
Q to E reaction
PRPP synthase is regulated by what?
Inhibited by GDP and ADP