Term
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Definition
defect in structural gene for apo B-100. Fat malabsorption and hypocholesterolemia, severe GI symptoms.
Treatment: restriction of TGs w/ long-chain FAs b/c medium-chain TGs don't req chylomicron formation but are transported by albumin as free FAs. |
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Term
| Lipoprotein Lipase Deficiency & Apoprotein C-II Deficiency |
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Definition
both characterized by
- elevated plasma chylomicrons and TG conc.
- repeated attacks of abdominal pain, pancreatitis, hepatosplenomegaly.
Treatment: restriction of fat in diet. |
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Term
| 3 Methods to reduce lipid absorption |
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Definition
(1) Fake Fats - substitute fake fats (without glycerol backbone) for TGs since they will not be recognized by lipases (i.e. olestra has a sucrose core in place of glycerol)
(2) Lipase Inhibitors - tetrahydrolipistatin inhibits gastric & pancreatic lipase; reduces hydrolysis of TGs limiting free FAs (e.g. orlistat and Alli) but may block absorption of fat soluable vitamins
(3) FATP4 blocker - since FATP4 is major transporter of FFAs into enterocytes, it may be a good future drug target
(3) |
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Term
| 4 Steps of B-Oxidation of FAs |
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Definition
(1) Acyl-CoA DH - (acyl CoA -> tans-Enoyl CoA)
(2) Enoyl -CoA Hydrase - (trans-enoyl CoA -> 3-Hydroxyacyl CoA)
(3) B-Hydroxyacyl-CoA DH - (hydroxyacyl CoA -> 3-Ketoacyl CoA)
(4) 3-Ketoacyl-CoA Thiolases - (3-Ketoacyl -> Acyl CoA + Acetyl CoA) |
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Term
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Definition
| largest, lightest lipoprotein; synthesized in intestine; enter circulation; transport TGs to peripheral cells and liver. |
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Term
| Very Low Density Lipoproteins (VLDLs) |
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Definition
| Originate in liver; secreted into circulation; transport endogenously synthesized TGs to peripheral cells for storage or use |
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Term
| Intermediate Density Lipoproteins (IDLs)` |
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Definition
| producing during conversion of VLDL to LDL; contain TGs and Cholesterol esters |
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Term
| Low Density Lipoproteins (LDLs) |
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Definition
| from metabolism of VLDLs, core mostly cholesterol esters of hepatic and intravascular origin; delivers cholesterol to peripheral cells. |
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Term
| High Density Lipoproteins (HDLs) |
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Definition
| synth and sec in small intestine and liver; 50% protein, 30% phospholipid, remainder free and esterified cholesterol. |
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Term
| Pancreatic Triglyceride Lipase (PTL) |
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Definition
| removes FAs from sn-1 and sn-3 positions of TGs; |
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Term
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Definition
| Fatty acid transport protein 4 - highly expressed in enterocytes; plays major role in uptake of FAs from intestinal lumen. |
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Term
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Definition
autosomal recessive; no functional peroxisomes, LE: 12 weeks; very high plasma FAs (long-chain, 26C).
peroxisomes play vital role in B-ox of FAs. Although mito B-ox fine, carnitine shuttle very inefficient in transport of long FAs. |
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Term
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Definition
autosomal recessive; accumulation of phytanic acid in plams & tissue.
symp: peripheral neuropathy, ataxia, retinitis pigmentosa; bone/skin changes. phytanic acid has 4 methyl grps (pos 3,7,11,15)
position 3 FAs connot be degraded; must be modified by a-ox.
so, degen of 3 methyl branched FAs FA req a-ox |
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Term
| What happens in the case of high ATP and acetyl CoA (high fat diet) during conditions of carb starvation? FA syth? Why or why not? |
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Definition
| excess Acetyl-CoA is not used for FA synth b/c low carb levels lead to depletion of OAA needed to form citrate (to transfer Acetyl-CoA to cytosol). In effect, ketone bodies are formed. |
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Term
What effect (pos/neg) do the following have on lipogenic enzymes?
(1) high carb diet
(2) high insulin
(3) high fat low carb diet
(4) fasting |
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Definition
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Term
| What 2 molecules comprise ceramide? |
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Definition
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Term
| What characterizes a sphingosine? |
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Definition
|
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Term
| What comprises sphingomyelin? |
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Definition
| ceramide + phosphatidylcholine |
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Term
| What class of molecule to you form when you add a carbohydrate to a ceramide? |
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Definition
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Term
| What characterizes gangliosides and what organ contains the highest concentration of gangliosides? |
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Definition
| 1 or more N-acetylneuraminic acids (sialic acid residues) and the brain. |
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Term
| Where are the highest concentrations of sphingolipids found and in what organelle are they degraded? |
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Definition
the myelin sheath membrane of neurons and in lysosomes
Funcion: cell-cell recognition, contact inhibition of growth, signal transduction, second messengers |
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Term
| What enzyme is deficient in Tay-Sachs disease? |
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Definition
| B-hexoaminidase A (converts ganglioside GM2 to Cer-Glc-Gal-NeuAc) |
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Term
| What enzyme is deficient in Sandhoff's disease? |
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Definition
| B-Hexoaminidases A & B (converts globoside to Cer-GLC-Gal-Gal) |
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Term
| The majority of diseases that we discussed are effects of deficiencies in what type of pathway? What is the cause of the pathology (hepato- and splenomegaly, mental retardation, early death) |
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Definition
| Degredation of sphingolipids... and accumulation of the substrate. |
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Term
| What is the enzyme def involved in Metachromic leukodystrophy? |
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Definition
| arylsulphatase A (converts sulphatide to Cer-Gal) |
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Term
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Definition
| def of a-galactosidase (removes Gal from Cer-Glc-Gal) |
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Term
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Definition
| B-glucosidase (removes Glc from Cer-Glc) |
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Term
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Definition
| B-galactosidase def (removes Gal from Cer-Gal) |
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Term
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Definition
def in sphingomyelinase (converts sphingomyelin to ceramide)
Note: sphingomyelin is a ceramide + phosphatidylcholine) |
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Term
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Definition
| def in ceraminidase (breaks ceramide into Sphingosine + FA) |
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Term
| What is phosphatidate (1) used for and(2) made from? |
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Definition
phosphatidate is involved in biosynth of TGs and phospholipids (phosphatidylserine and phosphatidylinositol)
it is made from DHAP and Glycerol (or Glycerol-3-P) |
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Term
| Where is leptin produced? What does it do? Does it have a long or short term effect? |
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Definition
| produced in adipocytes, decreases appetite, increases caloric expenditure, long term effect |
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Term
| Where are ghrelins released? What do they do to appetite? Short and/or long-term effect? |
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Definition
| produced by stomach, increase appetite, short and long term effects. |
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Term
| Name a few lipogenic enzymes? |
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Definition
| acetyl-CoA, FA synthase, citrate lyase, malic enzyme, DH of the PPP (Glc-6-P DH, etc.) |
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