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30 Cards in this Set
- Front
- Back
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lipid storage
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TAG's in adipose
droplets surrounded by perilipin in cytosol |
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pathway with HSL
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TAG mobilization in fat cell
with desnutrin (induced by glucocorticoids) HSL induced by glucagon (phosphorylation via cAMP) catalyzes rate-limiting rxn converts DGs to MGs |
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pathway with desnutrin
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TG mobilization from adipose
induced by glucocorticoids catalyzes conversion from TG to DG |
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role of perilipin in FA oxidation
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TAG mobilization
gets pore when phosphorylated allows HSL in lipid droplet |
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TAG mobilization
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glucagon or cortisol signal
phosphorylate perilipin & HSL (via PKA & ATP) desnutrin cats TG to DG HSL converts DG to MG MG lipase converts to FFA + glycerol (fuel for gneogen) |
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carrier protein for FFA
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albumin
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effect of cortisol on TAGs
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activate desnutrin (to produce DGs) via nuclear regulation
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effect of glucagon on TAGs
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phosphorylate catabolic pathways via cAMP & PKA
- perilipin (pore) - HSL (DG to MG) |
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effect of insulin on TAGs
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inactivate enzymes for mobilization (HSL & Pore in perilipin)
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products (& uses) from beta oxidation
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Acetyl CoA
- cholesterogenesis - ketogenesis - Activation of pyruvate carboxylase (generates OAA for gluconeogenesis & TCA- ABC enzyme) ATP & NADH (PH for synth) - to drive gluconeogenesis ATP for cells in general - esp heart & skel - not RBC (no mito) generates heat (brown fat, great vessels neonate) |
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beta oxidation occurs in
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mitochondria of muscle (heart & skel) and liver
(synthesis in cytosol- glucose rxns in cytosol) |
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process for FA oxidation
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liberate FAs from adipose
carry to liver (albumin) in to mito(Carnitine) acetylate (to keep in cell) oxidation (removes 2 Cs per cycle) odd chains use propionate to methylmalonyl CoA then succinyl CoA to TCA unsaturated convert cis to trans then finish |
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fate of odd chain FAs
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oxidated until propionate
carboxylated to methylmalonyl CoA then succinyl CoA (w/B12) to TCA |
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rate limiting enzyme for beta oxidation
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acetyl CoA synthetases
60% at ER 20% at mito membrane 20% at peroxisomes |
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enzymes for FA oxidation
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transport into mito
- Acyl CoA synthetase (traps) - CPT 1 outer membrane - CPT 2 inner membrane (mito catalyze synthetase) - carnitine translocase (transport in & out) Dehydrogenases - ACoA Dh- gives enoyl CoA (then hydrated to beta HA CoA) - beta hydroxyacyl CoA gives beta ketoacyl CoA cleaved via CoASH gives ACoA (returns for next FA) |
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hypoglycemia in Newborns
caused by |
MCAD- deficient fatty acylCoA Dh
explains 50% of SIDS |
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characteristics of Carnitine
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non essential
made in liver & kidney from lysine & methionine uses B6 babies can't make but get SCFAs from breast milk |
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acyl carnitine
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high energy compound
transport form (to mito) of FA |
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seizure med that inhibits beta ox
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valproic acid
resembles FA liver conjugates to carnitine less carnitine available |
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core reactions of beta oxidation
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redox- ACoA Dh (FADH2)
hydration- enoyl hydratase redox- beta HA Dehydrogenase (NADH) thiolytic cleavage- beta ketothiolase |
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characteristics of fatty acylCoA Dh rxn
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oxidation rxn
fatty acylCoA to enoyl CoA (double bond) embedded in ETC generates FADH2 only works if 2 H's on beta C (if alc to ketone use NAD to NADH b/c oxidation) |
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energy available in a FA (equation)
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(# C's/2)- 1
x 2 (FADH2) x 3 (NADH) # Cs/2 x 12 (ATP equivs from TCA) |
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ancillary rxns in beta oxidation
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odd carbon dbl bond (oleic acid)
- delta 3,4 enoyl CoA isomerase & hydratase) - moves dbl bond off of beta even carbon double bond (lineolate) - 2,4 dienoyl CoA reductase (uses NADPH) then isomerase FAs w/CH3 on odd # Cs -alpha hydroxylase (removes carboxyl) (uses O2, Fe & alpha KG) (NOT NADPH & O2) -phytanoyl CoA lyase (removes formyl CoA) -generates propionyl CoA -disorder is Refsum's |
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RQ for glucose
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1
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RQ for lipid
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0.71
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RQ for protein
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0.82
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Refsum's caused by
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inability to oxidize FA w/odd C methyl gp (eg. Pytanic acid)
problem with alpha hydroxylase (in peroxisome) Fe, O2, alphaKG, CoA (not NADPH & O2) |
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Zellweger's Disease caused by
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congenital peroxisomal (absence)disorder
accumulate VLCFA's |
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function of peroxisome in FA ox
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VLCFA's can't do beta ox
(24 c or more) into peroxisome generate octanoyl CoA (8c's) - to mito generate CO2 & H20 and ACoA - to mito uses ATP & CoASH |
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essential vitamin for carnitine synthesis
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B6
uses lyseine &/or methionine |
