Term
| Where do catabolic rxns take place? Anabolic? |
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Definition
| Catabolic in mito. Anabolic in cyto. Exception - glycolysis in cyto (bc in RBCs also, which have no mito!) |
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Term
| How is the rate limiting step determined via assays on relative activities? |
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Definition
| Compare Keq and Mass Axn Ratio. Similar means enzyme is not being limited from reaching close to full capacity. Far apart means likely rate limiting. |
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Term
| Which assay measures amount of protein (enzyme)? |
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Definition
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Term
| Which assay measures amount (size) of mRNA? |
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Definition
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Term
| Which assay measures level of transcription? |
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Definition
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Term
| Which assay measures half-life? |
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Definition
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Term
| Describe the 5 glucose carriers. |
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Definition
GLUT 1,3 - every cell, low Km, constituitively active.
GLUT 2 - pancreas & liver, high Km
GLUT 4 - adipose & muscle, translocate to plasma mbren in presence of high blood glucose.
GLUT 5 - active! Kidney & GI, uses ATP |
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Term
| Caffeine inhibits phosphodiesterase - what is the affect of this on axn of glucagon? |
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Definition
| cAMP not broken down to AMP --> continues to P target enzymes --> keeps glucagon activated pathways active |
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Term
| Receptor types - insulin vs glucagon. |
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Definition
| Insulin = RTK, glucagon = GPCR |
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Term
| Type I vs Type II diabetes. |
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Definition
Type I - decr pdxn of insulin by B cells, usually autoimmune.
Type II - ability to uptake/utilize insulin is desensitized. Can be due to mutation in receptor, 2nd messenger pathway. |
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Term
| Glucokinase vs hexokinase. |
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Definition
Hexokinase - all cells, low Km for glucose, constituitively active, inhib by products.
Glucokinase - liver/pancreas, high Km, hormonal regulation at txnl level, no product inhibition. |
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Term
| Effect of alcohol on glycolysis. |
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Definition
| Oxdn of alcohol depletes NAD+ which is necessary for G3P-->13bisPG. |
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Term
| Hormonal reg of glycolysis? |
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Definition
1) PFK - stim by F2,6bisP; (F6P-->F2,6bisP is by PFK2 which is deP/activated by insulin)
2) Pyruvate Kinase - insulin deP/activates |
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Term
| 3 inhibitors of glycolysis. |
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Definition
Heavy metals - inhib G3PDH (G3P build up);
Arsenic - competes w Pi for G3P, skips intermediate, 2 less ATP/glucose;
Fluoride - stops glycolysis @ enolase. |
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Term
| Consequences/treatment of Pyruvate Kinase deficiency. |
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Definition
| Hemolytic anemia due to RBCs being completely dependent on glycolysis for ATP; reqs transfusion of normal RBCs. |
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Term
| Irreversible steps of glycolysis. |
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Definition
| Hexo/glucokinase, PFK, Pyruvate Kinase |
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Term
| Consequences of aldolase B deficiency. |
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Definition
| hereditary fructose intolerance; build up of F1P - toxic @ high levels. |
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Term
| 4 Possible fates of pyruvate |
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Definition
| Acetylaldehyde (yeast), Lactate, AcCoA, OAA |
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Term
| Why would Pyruvate --> lactate over -->AcCoA? |
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Definition
| Lactate when oxidized NAD+ is needed (RBCs, exercising muscle). |
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Term
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Definition
M in muscle/RBCs - pyruvate-->lactate;
H in heart/brain - lactate-->pyruvate |
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Term
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Definition
Tissues --> oxd to pyruvate -->PDH -->TCA;
Liver --> glucose via gluconeogenesis |
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Term
| Where in cell does LDH rxn occur? PDH? |
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Definition
| LDH - cyto; PDH - mito (gets in via carrier) |
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Term
| Why is lactate so important for the cells that produce it? |
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Definition
| Used for rapid glycolysis and in cells w/o mito which can't oxidize NADH --> NAD+ via respiratory chain. |
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Term
| Overall eqn of anaerobic glycolysis. |
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Definition
| Glucose --> 2 Lactate + 2 ATP |
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Term
| 3 Enzymes of PDH and their co-factors. |
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Definition
| E1 - TPP (B1), E2 - Lipoic Acid (B), E3 - FAD (B2, riboflavin) |
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Term
| Metabolite control of each step of PDH. |
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Definition
| All inhib: E1 by ATP (high energy), E2 by AcCoa (product), E3 by NADH (product) |
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Term
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Definition
PDH Kinase --> P-El (inhibitory)
PDH phosphatase --> deP E1 (activates)
Phosphatase incr by insulin but NO glu/epi control! |
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Term
| Net yield of ATP when glucose is completely oxd to CO2 + H2O. |
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Definition
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Term
| Rate limiting step of Krebs cycle and its regulation. |
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Definition
ICDH (isocitrate --> aKG);
(-)ATP, NADH;
(+) ADP, Ca2+ |
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Term
| How do high levels of ATP regulate Krebs? |
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Definition
| inhibit irreversible steps |
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Term
| Role of anapleurotic rxns in Krebs? |
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Definition
| replenish OAA and other intermediates. |
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Term
| Where in cell does Krebs occur? |
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Definition
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Term
| How can fumarate be regenerated? |
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Definition
| Urea cycle, purine synth, catabolism of phenylalanine/tyrosine |
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Term
| Succ CoA is used to make... |
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Definition
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Term
| Citrate is necessary for... |
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Definition
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