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23 Cards in this Set
- Front
- Back
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characteristics of COX
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complex structure
tiny amounts in body hard to purify unstable (t 1/2 = seconds) |
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eichosonoid hormone characteristics
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"1 pass effectors"
paracrine (not endocrine) made on spot quick action then gone |
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functions of eichosonoids
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inflammation
reproduction (RU 486 & PGE2) inhibit HCL secretion BP regulation BF to kidney (increase GFR for elderly) clotting -TXA2 & PGE2 -PGI2 (cyclin) inhibits ductus arteriosis -indometh closes -PGE2 keeps open |
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stearic acid
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C18:0
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arachadonic acid
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C20:4
hairpin structure head/tail association resembles prostanoic acid (parent structure for PGs) |
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families of prostaglandins
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PGA (most oxidized)
PGE PGF (most reduced) |
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common characteristics of PGs
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2 double bonds (delta 5)
-after 5 & 13 C 15 hydroxyl |
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synthesis of arachadonic acid
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from linoleic
ACoA synthetase delta 6 desaturase elongase delta 5 desaturase arachidonoyl CoA |
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ACoA synthetase
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gives linoleoyl CoA (from linoleic)
uses ATP |
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desaturase always moves toward
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carboxyl end
by count of 3 |
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Elongase always...
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lengthen chain by 2
forms malonyl CoA blows off CO2 always at carboxyl end |
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COX 1
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gastric mucosa
constituatively active renal BF plts, vasc endo, kidney |
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COX 2
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MPs, monocytes, sm muscle
inducible -PAF, LPS (bugs), IL-1 |
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regulation of COX
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many levels
substrate avail induction of COX2 NSAIDs |
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annexin
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ANX 1
-blocks PLA2 -binds lipids (cell membrane) -glucocorticoids induce ANX1 |
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reservoir for arachadonic acid
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phosphotidylinositol
(aa would detergent & inhibit enzymes) |
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rate limiting step of eichosonoid synth
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PLA2
releases arachadonic acid (from phosphotydilinositol) inhibited by ANX1 |
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COX reaction
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O2 straddles ring
"bisdioxygenation" gives PGG2 |
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PGG2
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intermediate in COX pathway
NOT eichosonoid |
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hydroperoxidase
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takes PGG2 to PGH2
uses GSH to GSSG isomerases determine fate |
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unique structure in eichosonoids
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TXA2-
"weird O in middle of ring" |
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aspirin effect on eichoso's
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covalent modifier of COX
via serine in pocket |
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non-aspirin NSAID effect on eichoso's
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covers mouth of serine pocket (active site)
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