Term
| what are the derivatives for phenylalanine? |
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Definition
| tyrosine (thyroxine) -> dopa (melanin) -> dopamine -> NE -> epi |
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Term
| what are the derivatives for tryptophan? |
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Definition
| (via B6) niacin -> NAD+/NADP+. (via BH4) serotonin -> melatonin. |
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Term
| what are the derivatives for histidine? |
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Definition
|
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Term
| what are the derivatives for glycine? |
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Definition
| (via B6) porphyrin -> heme |
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Term
| what are the derivatives for arginine? |
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Definition
|
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Term
| what are the derivatives for glutamate? |
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Definition
| (via B6) -> GABA. also, glutathione. |
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Term
| what characterizes phenylketonuria? |
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Definition
| decreased phenylalanine hydroxylase (which converts phenylalanine to tyrosine). this leads to excess phenylketones (phenylacetate, phenyllactate, and phenylpyruvate) in urine, musty body odor, growth retardation, seizures, fair skin, and eczema. tyrosine becomes very important diet-wise. maternal PKU is also possible due to lack of proper dietary therapy during pregnancy, this may lead to: microcephaly, mental retardation, growth retardation and congenital heart defects in the infant. |
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Term
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Definition
| a congenital deficiency of homogentisic acid oxidase (degradative pathway of tyrosine to fumarate) = dark connective tissue, brown pigmented sclera, black urine on standing, and possible debilitating arthralgias. |
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Term
| what 2 things is albinism usually a congenital deficiency in? |
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Definition
| 1) tyrosinase (autosomal recessive, inability to synthesize melanin from tyrosine) or 2) defective tyrosine transporters (decreased tyrosine, and thus melanin). this can result from lack of migration of neural crest cells. |
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Term
| what are the 3 forms of homocystinuria (all are autosomal recessive)? |
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Definition
| 1) cystathionine synthase deficiency [tx: decreased met, increased cysteine and B12]. 2) decreased affinity of cystathionine synthase for pyridoxal phosphate [tx: increased B6). 3) homocysteine methyltransferase deficiency. *all forms result in excess homocysteine, cysteine becomes essential. pts present with: increased homocystine in urine, mental retardation, osteoporosis, tall stature, kyphosis, lens subluxation (downward+inward), and atherosclerosis (stroke + MI). |
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Term
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Definition
| a hereditary defect of the renal tubular amino acid transporter for cysteine, ornithine, lysine, and arginine in the PCT. this can lead to precipitation of cystine kidney stones (staghorn). autosomal recessive. tx: acetazolamide. cystine is made up of 2 cysteines connected by a disulfide bond. |
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Term
| what is maple syrup urine disease? |
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Definition
| blocked degradation of branched AAs (Ile, Leu, Val = I Love Vermont/branches) due to *decreased alpha-ketoacid dehydrogenase. this leads to increased alpha-ketoacids in blood, esp Leu and severe CNS defects, mental retardation, and death. |
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Term
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Definition
| an autosomal recessive disorder characterized by a defective neutral AA transporter on renal/intestinal epithelial cells. it leads to tryptophan excretion in urine and decreased gut absorption. leads to pellagra (diarrhea, dementia, dermatitis, death) |
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Term
| what kind of receptor is associated with glucagon? |
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Definition
| adenylyl cyclase -> cAMP -> protein kinase A |
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Term
| what kind of receptor is associated with insulin? |
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Definition
|
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Term
| what coordinates glycogenolysis w/muscle activity? |
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Definition
| Ca++/calmodulin, which activates glycogen phosphorylase kinase |
|
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Term
| what are the different bonds in glycogen? |
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Definition
| branches: alpha (1,6) bonds. linkages: alpha (1,4) bonds. |
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Term
| what is the mnemonic for the glycogen storage diseases? |
|
Definition
| Very Poor Carbohydrate Metabolism. (Von Gierke's, Pompe's, Cori's, McArdle's). |
|
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Term
| what is von gierke's disease? |
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Definition
| glycogen storage disease type I: a deficiency in glucose-6-phosphatase, which leads to severe fasting hypoglycemia, increased glycogen in liver, increased blood lactate and hepatomegaly (impairs the ability of the liver to produce free glucose from glycogen and from gluconeogenesis). |
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Term
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Definition
| glycogen storage disease type II: deficiency in lysosomal alpha 1-4 glucosidase (acid maltase) = cardiomegaly/systemic findings (liver/muscle) due to accumulation of glycogen in the lysosome. "pompe's trashes the pump" |
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Term
|
Definition
| glycogen storage disease type III: milder form of von gierke's w/normal blood lactate levels -> due to a debranching enzyme (1,6) deficiency. gluconeogenesis is intact. |
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|
Term
| what is mcardle's disease? |
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Definition
| glycogen storage disease type V: increased glycogen in muscle, but cannot break it down - leads to painful muscle cramps and myoglobinuria w/strenuous exercise, due to skeletal muscle glycogen phosphorylase. "mcardles = muscle" |
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Term
| what is the most common sphingolipidoses/lysosomal storage disease? |
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Definition
| gaucher's. deficient in beta-glucocerebrosidase = accumulation of glucocerebroside. autosomal recessive. hepatosplenomegaly, aseptic necrosis of the femur, bone crises, and gaucher cells (macrophages which look like balled up paper). |
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Term
| what characterizes fabry's disease (sphingolipidoses/lysosomal storage disease)? |
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Definition
| alpha-galactosidase A deficiency = peripheral neuropathy of hands/feet, angiokeratomas, and cardiovascular/renal disease due to ceramide trihexoside accumulations. X linked recessive. |
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Term
| what characterizes niemann-pick disease (sphingolipidoses/lysosomal storage disease)? |
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Definition
| sphingomyelinase deficiency, accumulation of sphingomyelin = progressive neurodegeneration, hepatosplenomegaly, cherry-red spot on macula, and foam cells. autosomal recessive. |
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Term
| what characterizes tay-sachs disease (sphingolipidoses/lysosomal storage disease)? |
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Definition
| deficiency in hexosaminidase A (tay saX), GM2 ganglioside accumulation = progressive neurodegeneration, developmental delay, cherry red spot on macula, lysosomes w/onion skin - NO hepatosplenomegaly (vs niemann pick). autosomal recessive. |
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Term
| what characterizes krabbe's disease (sphingolipidoses/lysosomal storage disease)? |
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Definition
| glucocerebrosidase deficiency, galactocerebroside accumulation = peripheral neuropathy, developmental delay, optic atrophy, and globoid cells. autosomal recessive. |
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Term
| what is metachromatic leukodystrophy (sphingolipidoses/lysosomal storage disease)? |
|
Definition
| arylsulfatase A deficiency, cerebroside sulfate accumulations = central and peripheral demyelination w/ataxia and dementia. autosomal recessive. |
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Term
| what is hurler's syndrome (mucopolysaccharidoses/lysosomal storage disease)? |
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Definition
| alpha-L-iduronidase deficiency, heparan/dermatan sulfate accumulations = developmental delay, gargoylism, airway obstruction, corneal clouding, and hepatosplenomegaly. autosomal recessive. |
|
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Term
| what is hunter's syndrome (mucopolysaccharidoses/lysosomal storage disease)? |
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Definition
| iduronate sulfatase deficiency, heparan/dermatan sulfate accumulations = mild hurler's and aggressive behavior (no corneal clouding). X-linked recessive. (hunter's see clearly and aim for the X). |
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Term
| what is the mnemonic for which shuttles are involved in fatty acid synthesis/breakdown? |
|
Definition
| citrate/sytrate = synthesis (occurs in cytoplasm). carnitine/carnage = breakdown (occurs in mitochondrial matrix). |
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Term
| what is the effect of a carnitine deficiency? |
|
Definition
| inability to transport LCFAs into the mitochondria, resulting in toxic accumulation = weakness, hypotonia, and hypoketotic hypoglycemia. |
|
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Term
| what is the effect of a acyl-coa dehydrogenase deficiency? |
|
Definition
| increased dicarboxylic acids and decreased glucose/ketones. |
|
|
Term
| what ketone bodies are fatty acids and amino acids metabolized to in the liver? |
|
Definition
| acetoacetate and beta-hydroxybutyrate |
|
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Term
| what is depleted for gluconeogenesis in prolonged starvation and diabetic ketoacidosis? |
|
Definition
| oxaloacetate (stalls TCA -> production of ketones) |
|
|
Term
| what is oxaloacetate shunted towards in alcoholism? |
|
Definition
| malate, via NADPH (stalls TCA -> production of ketones) |
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Term
|
Definition
|
|
Term
| what does pancreatic lipase do? |
|
Definition
| degradation of dietary TG in the small intestine |
|
|
Term
| what does lipoprotein lipase do? |
|
Definition
| degrades TG circulating in chylomicrons and VLDLs |
|
|
Term
| what does hepatic TG lipase do? |
|
Definition
| degrades the TG remaining in IDLs |
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|
Term
| what does hormone sensitive lipase do? |
|
Definition
| degrades TG stored in adipose |
|
|
Term
| what does lecithin cholesterol acyltransferase (LCAT) do? |
|
Definition
| catalyzes esterification of cholesterol |
|
|
Term
| what does cholesterol ester transfer protein (CETP) do? |
|
Definition
| mediates transfer of cholesterol esters to other lipoprotein particles |
|
|
Term
| what does apolipoprotein A1 do? |
|
Definition
|
|
Term
| what does apolipoprotein B-100 do? |
|
Definition
| Binds to LDL receptor, mediates VLDL secretion |
|
|
Term
| what does apolipoprotein C-II do? |
|
Definition
| Cofactor for lipoprotein lipase |
|
|
Term
| what does apolipoprotein B-48 do? |
|
Definition
| mediates chylomicron secretion |
|
|
Term
| what does apolipoprotein E do? |
|
Definition
|
|
Term
| what does the chylomicron do? |
|
Definition
| delivers dietary TGs to peripheral tissue. delivers cholesterol to the liver in the form of chylomicron remnants (mostly depleted of TGs). secreted by intestinal epithelial cells. |
|
|
Term
| what apolipoproteins are associated w/chylomicrons? |
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Definition
|
|
Term
| what apolipoproteins are associated w/VLDLs? |
|
Definition
|
|
Term
| what apolipoproteins are associated w/IDLs? |
|
Definition
|
|
Term
| what apolipoproteins are associated w/LDLs? |
|
Definition
|
|
Term
|
Definition
| cholesterol transport from the periphery to the liver, acting as repositories for apoC and apo E. |
|
|
Term
| what characterizes hyperchylomicronemia (familial dyslipidemia type 1)? |
|
Definition
| increased chylomicrons, elevated TG/cholesterol blood levels - due to a lipoprotein lipase deficiency or altered apolipoprotein C-II. causes pancreatitis, hepatosplenomegaly, and eruptive/pruritic xanthomas. *no increased risk for atherosclerosis. |
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|
Term
| what characterizes familial hypercholesterolemia (familial dyslipidemia type IIa)? |
|
Definition
| absent or decreased LDL receptors = increased LDL/cholesterol; accelerated atherosclerosis, tendon (achilles) xanthomas, and corneal arcus. |
|
|
Term
| what characterizes hypertriglyceridemia? |
|
Definition
| hepatic overproduction of VLDL = elevated TG blood levels and pancreatitis |
|
|
Term
| what is hypertriglyceridemia? |
|
Definition
| a hereditary inability to synthesize lipoproteins due to deficiencies in apoB-100 and apoB-48. autosomal recessive. symptoms appear in the first few months of life - intestinal bx shows accumulation w/in enterocytes due to inability to export absorbed lipid as chylomicrons. findings: failure to thrive, steatorrhea, acanthocytosis, ataxia, and night blindness |
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