Flashcards in Biochem metabolism Deck (129)
During pyruvate metabolism, What processes occur in the cytosol? Mitochondria?
Alanine & lactate are produced in cytosol;
Oxaloacetate & Acetyl-CoA are produced in the mitochondria
Where does the TCA cycle reactions occur?
ETC & oxidative phosphorylation has a main function of what?
put H+ into inter membrane space to use as a gradient to power ATPase
What drug(s) inhibits complex 1 of ETC?
rotenone, barbituates, amytal, MPTP (synthetic demorol) => parkinson cause
What drug(s) inhibits complex 3 of ETC?
What drug(s) inhibits complex 4 of ETC?
Cyanide, CO, NH3-, H2S
What drug(s) inhibits complex 5 of ETC?
What drug(s) inhibits CoQ of ETC
Name ETC inhibitors along w/ action
rotenone, CN, antimycin A, CO => Directly inh electron transport leading to decreased proton gradient & ATP synthesis block
Name ATP synthase (complex 5) inhibitors along w/ action
Oligomycin=> directly inhibits mitochondrial ATPsynthase leading to increased proton gradient => NO ATP PRODUCED bc electron transport stops
Describe how uncoupling agents affect the ETC
increase permeability of inner Mt membrane leading to decreased proton gradient & increased O2 consumption => ATP synthesis stops but electron transport continues so HEAT IS PRODUCED
What are uncoupling agents of ETC?
2,4 DNP (wood preserver);
Aspirin (overdose fever);
thermogenin (brown adipose - baby fat)
What are the irreversible enzymes of gluconeogenesis? name location & substrate/product
pyruvate CB in Mt (biotin, ATP, acetyl-CoA)= pyruvate to OAA;
PEP CB in cytosol (GTP) = oxaloacetate to phosphoenolpyruvate;
F-1,6-BPase in cytosol = F-1,6-BP to Fructose-6-P;
G-6-Pase in ER = Glucose-6-P to glucose
Where does gluconeogenesis occur primarily? where can it not occur?
occurs in liver
cannot in muscle bc it has no G-6-Pase
What type of FA chains can serve as glucose sources? Why?
Odd bc yields 1 propionyl-CoA during metabolism to enter TCA (succinyl-CoA) to undergo gluconeogenesis
Even only yield acetyl-CoA so cannot make new glucose
What is the purpose of the HMP shunt?
provide NADPH from G-6-P for reductive rxn then produces ribose for nucleotide syn & glycolytic intermediates
Where do the 2 phases of HMP shunt occur? what is the difference in them?
Oxidative is irreversible using G-6-P DH (rate limiter) & NADP+to produce CO2, NADPH, Ribulose-5-P for PRPP generation for nucleotide syn
Nonoxidative is reversible & requires Thiamine & transkelotases to produce ribose-5-P, G3P, F6P
What cells can use respiratory burst (oxidative burst)? What is involved?
Neutrophils & monocytes activate membrane bound NADPH oxidase for immune response & release of ROI
What are the basic roles of NADPH?
create AND neutralize ROIs
Where in the neutrophil or monocyte does respiratory burst occur?
What is the result if NADPH oxidase is deficient?
chronic granulomatous disease
How does a WBC of pt w/ chronic granulomatous disease make ROI?
utilize H2O2 that is generated by invading organism (bacterial catalase) & convert it to ROI
If a patient is deficient in G6PD or NADPH oxidase, what type of infection risk is present?
catalase positive (S. aureus, Aspergillus) bc they neutralize own H2O2 leaving WBCs w/o ROI to fight infection
What is the MC human enzyme deficiency? How is it inherited & who shows the most prevalence?
XLR of G6PD deficiency that is MC in blacks assoc w/ increased malarial resistance
What is the result of G6PD deficiency in RBCs?
NADPH is decreased so cannot keep glutathione reduced therefore free rad & peroxides occur leading to damage & hemolytic anemia
What will be seen on a blood smear in a pt w/ G6PD deficiency?
Heinz bodies => oxidized Hgb precipitated w/in RBCs
Bite cells result from splenic macs taking out heinz bodies thus leading to hemolytic anemia
What can induce a person w/ G6PD deficiency leading to hemolytic anemia?
fava beans (mediteranean food); sulfonamides, Primaquine, anti-TB; infection
Essential fructosuria has a defect in what and how is it inherited? What will diagnose & what Sx?
AR benign defect in fructokinase will lead to fructose in blood & urine
rare osmotic diarrhea
Fructose intolerance has a defect in what and how is it inherited?
AR deficiency in aldolase B leading to accumulation of F1P which binds phosphate resulting in inhibition of glycogenolysis & gluconeogenesis