Term
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Definition
| lipoprotein aggregates into which the products of lipase action are packaged with dietary cholesterol & specific proteins after being reconverted to triacylglycerols when they diffuse into the epithelial cells lining the intestinal surface |
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Term
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Definition
| lipid-binding proteins in the blood that are responsible for the transport of triacylglycerols, phospholipids, cholesterol, & cholesterol esters between organs |
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Term
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Definition
| when apolipoproteins combine with lipids; spherical aggregates with hydrophobic lipids at the core & hydrophilic protein side chains & lipid head groups at the surface |
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Term
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Definition
| an extracellular enzyme in the capillaries; once activated by apoC-II, it hydrolyzes triacylglycerols to fatty acids & glycerol which are taken up by cells in the target tissues |
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Term
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Definition
| a family of proteins that restrict access to lipid droplets to prevent untimely lipid mobilization |
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Term
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Definition
| fatty acids that are released; pass from adipocyte into the blood where they bind to the blood protein serum albumin |
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Term
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Definition
| phosphorylates the glycerol released by lipase action; forms glycerol 3-phosphate which is oxidized to dihydroxyacetone phosphate |
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Term
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Definition
| a series of three enzymatic reactions through which FFAs of 14 or more carbons must pass in order to pass through the mitochondrial membranes |
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Term
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Definition
| a family of isoenzymes present in the outer mitochondrial membrane that catalyze the first reaction in the carnitine shuttle |
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Term
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Definition
| yielded when acyl-CoA synthetases catalyze the formation of a thioester linkage between the fatty acid carboxyl group & the thiol group of coenzyme A; the formation reaction is coupled to the cleavage of ATP to AMP & PPi |
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Term
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Definition
| uses its hydroxyl group to transiently attach to fatty acids destined for mitochondrial oxidation; forms fatty acyl-carnitine in the second reaction of the carnitine shuttle |
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Term
| carnitine acyltranferase I |
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Definition
| catalyzes the carnitine transesterification; exists in the outer membrane |
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Term
| acyl-carnitine/carnitine transporter |
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Definition
| how the fatty acyl-carnitine ester enters the matrix via facilitated diffusion; exists in the inner mitochondrial membrane |
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Term
| carnitine acyl-transferase II |
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Definition
| enzymatically transfers the fatty acid group from carnitine to intramitochondrial coenzyme A in the third & final step of the carnitine shuttle |
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Term
| trans-delta squared-enoyl-CoA |
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Definition
| yielded when dehydrogenation of fatty acyl-CoA produces a double bond between the alpha & beta carbon atoms |
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Term
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Definition
| three isoenzymes; each isoenzyme is specific for a range of fatty-acyl chain lengths; very-long-chain acyl-CoA dehydrogenase acts on fatty acids of 12 to 18 carbons; medium-chain acts on fatty acids of 4 to 14 carbons; short-chain acts on fatty acids of 4 to 8 carbons |
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Term
| electron-transferring flavoprotein (ETF) |
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Definition
| an electron carrier of the mitochondrial respiratory chain to which the reduced form of the dehydrogenase (formed when the electrons that are removed from the fatty acyl-CoA are transferred to FAD) immediately donates its electrons |
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Term
| beta-hydroxy-acyl-CoA (3-hydroxyacyl-CoA) |
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Definition
| the L stereoisomer formed when water is added to the double bond of trans-delta squared-enoyl-CoA in the second step of the beta-oxidation cycle |
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Term
| What is the relationship between beta-ketoacyl-CoA & beta-hydroxyacyl-CoA dehydrogenase? |
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Definition
| L-beta-hydroxyacyl-CoA is dehydrogenated to form beta-ketoacyl-CoA by the action of beta-hydroxyacyl-CoA dehydrogenase; NAD+ is the electron acceptor |
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Term
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Definition
| an electron carrier of the respiratory chain that allows for ATP to form from ADP as the electrons pass to O2 |
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Term
| acyl-CoA acetyltransferase (thiolase) |
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Definition
| catalyzes the fourth & final step of the beta-oxidation cycle; promotes reaction of beta-ketoacyl-CoA with a molecule of free coenzyme A to split off the carboxyl-terminal two-carbon fragment of the original fatty acid as acetyl-CoA |
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Term
| trifunctional protein (TFP) |
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Definition
| a multienzyme complex associated with the inner mitochondrial membrane which catalyzes the beta-oxidation reactions for fatty acyl chains of 12 or more carbons |
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Term
| delta cubed-delta squared-enoyl-CoA isomerase |
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Definition
| an auxiliary enzyme; isomerizes the cis-delta cubed-enoyl-CoA to the trans-delta squared-enoyl-CoA which is converted by enoyl-CoA hydratase into the corresponding L-beta-hydroxyacyl-CoA |
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Term
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Definition
| a three-carbon molecule formed in large amounts in cattle & other ruminant animals; forms during the fermentation of carbohydrates in the rumen |
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Term
| What is the relationship between methylmalonyl-CoA & propionyl-CoA carboxylase? |
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Definition
| propionyl-CoA is first carboxylated to form the D stereoisomer of methylmalonyl-CoA by propionyl-CoA carboxylase which contains the cofactor biotin |
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Term
| methylmalonyl-CoA epimerase |
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Definition
| enzymatically epimerizes D-methylmalonyl-CoA to its L stereoisomer |
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Term
| What is the relationship between methylmalonyl-CoA mutase & 5'-deoxyadenosylcobalamin (coenzyme B12)? |
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Definition
| methylmalonyl-CoA mutase requires coenzyme B12 (derived from vitamin B12) as its coenzyme |
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Term
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Definition
| the first intermediate in the cytosolic biosynthesis of long-chain fatty acids from acetyl-CoA (it increases in concentration whenever the animal is well supplied with carbohydrate) |
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Term
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Definition
| a family of nuclear receptors that are transcription factors that affect many metabolic processes in response to a variety of fatty acid-like ligands |
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Term
| medium-chain acyl-CoA dehydrogenase (MCAD) |
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Definition
| a molecule whose encoding gene can have a mutation which causes the most common genetic defect in fatty acid catabolism in US & northern European populations |
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Term
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Definition
| membrane-enclosed organelles of animal & plant cells in which the intermediates for beta oxidation of fatty acids are coenzyme A derivatives |
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Term
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Definition
| unable to make peroxisomes & therefore lack the metabolism unique to that organelle |
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Term
| X-linked adrenoleukodystrophy (XALD) |
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Definition
| peroxisomes fail to oxidize very-long-chain fatty acids apparently for lack of a functional transporter for these fatty acids in the peroxisomal membrane |
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Term
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Definition
| a process which has its own unique enzymes; the enzymes are located in the endoplasmic reticulum of the liver & kidney & the preferred substrates are fatty acids of 10 or 12 carbon atoms |
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Term
| 2 enzymes that act on the w carbon |
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Definition
1. alcohol dehydrogenase (oxidizes the hydroxyl group to an aldehyde)
2. aldehyde dehydrogenase (oxidizes the aldehyde group to a carboxylic acid, producing a fatty acid with a carboxyl group on each end) |
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Term
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Definition
| how branched fatty acids with the presence of a methyl group on the beta carbon (therefore beta oxidation is impossible) are catabolized in peroxisomes of animal cells |
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Term
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Definition
| very high blood levels of phytanic acid & severe neurological problems (including blindness & deafness) which results from a genetic defect in phytanoyl-CoA hydroxylase |
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Term
| 3 ketone bodies into which acetyl-CoA (formed in the liver during oxidation of fatty acids) can be converted for export to other tissues if it doesn't enter the citric acid cycle |
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Definition
1. acetone
2. acetoacetate
3. D-beta-hydroxybutyrate |
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Term
| Beta-hydroxy-beta-methylglutaryl-CoA (HMG-CoA) |
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Definition
| formed when acetoacetyl-CoA condenses with acetyl-CoA; cleaved to free acetoacetate & acetyl-CoA |
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Term
| acetoacetate decarboxylase |
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Definition
| decarboxylates acetoacetate to form acetone in very small amounts in healthy people if it is not spontaneously decarboxylated |
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Term
| beta-ketoacyl-CoA-transferase |
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Definition
| catalyzes the reaction in which acetoacetate is activated to its coenzyme A ester by transfer of CoA from succinyl-CoA (an intermediate of the citric acid cycle); also called "thiophorase" |
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Term
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Definition
| the condition that occurs when increased blood levels of acetoacetate & D-beta-hydroxybutyrate lower the blood pH |
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Term
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Definition
| close due to the increase of [ATP] caused by the higher rate of glucose metabolism; found in the plasma membrane |
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Term
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Definition
| oral medications used in the treatment of type 2 diabetes mellitus by binding to the SUR1 subunits of the K+ channels to close the channels & stimulate insulin release |
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Term
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Definition
| secreted due to lowered blood glucose; decreases insulin release |
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Term
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Definition
| the corticosteroid hormone released in response to stressors; comes from the adrenal cortex |
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Term
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Definition
| a relatively common disease (affects nearly 6% of the US population) that cause some degree of abnormality in glucose metabolism |
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Term
| 2 major clinical classes of diabetes mellitus |
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Definition
1. type 1 diabetes (insulin-dependent diabetes mellitus)
2. type 2 diabetes (non-insulin-dependent diabetes mellitus) (insulin-resistant diabetes) |
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Term
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Definition
| a condition that causes excretion of large amount of glucose in the urine |
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Term
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Definition
| the overproduction of ketone bodies; results in greatly increased concentration of ketone bodies in the blood & urine |
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Term
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Definition
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Term
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Definition
| peptide hormones produced by the adipose tissue when it acts as an endocrine organ |
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Term
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Definition
| an adipokine that, on reaching the brain, acts on receptors in the hypothalamus to curtail appetite |
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Term
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Definition
| a receptor encoded by the DB gene |
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Term
| What is the relationship between orexigenic neurons & neuropeptide Y (NPY)? |
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Definition
| The orexigenic neurons stimulate eating by producing & releasing NPY which causes the next neuron in the circuit to send the "eat!" signal to the brain |
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Term
| What is the relationship between anorexigenic neurons & alpha-melanocyte-stimulating hormone (alpha-MSH)? |
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Definition
| The anorexigenic neurons in the arcuate nucleus produce alpha-MSH (formed from its polypeptide precursor pro-opiomelanocortin) |
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Term
| 3 proteins for which phosphorylated-Tyr residues are a docking site |
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Definition
1. STAT 3
2. STAT 5
3. STAT 6
*STAT = signal transducers & activators of transcription* |
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Term
| AMP-activated protein kinase (AMPK) |
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Definition
| stimulated by leptin in liver & muscle; works to inhibit fatty acid synthesis & activate fatty acid oxidation to favor energy-generating processes |
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Term
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Definition
| a peptide hormone produced almost exclusively in adipose tissue to act as an adipokine that sensitizes other organs to the effects of insulin, protect against atherosclerosis, & inhibit inflammatory responses |
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Term
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Definition
| metabolic defects that resemble those of humans with type 2 diabetes; clear glucose from the blood only slowly |
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Term
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Definition
| a highly conserved Ser/Thr kinase; activated by abundant energy & nutrient supplies |
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Term
| peroxisome proliferator-activated receptors (PPARs) |
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Definition
| a protein family of ligand-activated transcription factors; respond to changes in dietary lipid by altering the expression of genes involved in fat & carbohydrate metabolism |
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Term
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Definition
| expressed primarily in liver & adipose tissue to turn on genes necessary to the differentiation of fibroblasts into adipocytes & genes that encode proteins required for lipid synthesis & storage in adipocytes |
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Term
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Definition
| expressed in liver, kidney, heart, skeletal muscle, & brown adipose tissue |
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Term
| What is the relationship between PPARdelta & PPARbeta? |
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Definition
| PPARdelta & PPARbeta are key regulators of fat oxidation & act by sensing changes in dietary lipid |
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Term
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Definition
| a peptide hormone produced in cells lining the stomach |
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Term
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Definition
| a peptide hormone secreted by endocrine cells in the lining of the small intestine & colon in response to food entering from the stomach |
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Term
| metabolic syndrome (syndrome X) |
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Definition
| the intermediate stage that precedes type 2 diabetes mellitus |
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