Flashcards in Biochemistry Deck (293)
Sodium Cyanide-Nitroprusside test
use to dx Cystinuria (causes urine to turn red-purple)
What disease may lead to pellagra?
-tryptophan excretion in urine and decreased absorption from gut; niacin (vit B3) is derived from tryptophan, so get niacin deficiency --> pellagra = diarrhea, dementia, dermatitis, death
In which organs/cells does glycogenolysis occur?
Skeletal muscle: glycogen--> glucose; glucose is rapidly metabolized during exercise
Hepatocytes: glycogen--> glucose to maintain blood sugar at appropriate levels
Names of the 4 glycogen storage diseases:
"Very Poor Carbohydrate Metabolism"
1) Von Gierkes - type 1 (glucose-6-phosphatase def)
2) Pompes - type 2 (alpha-1,4-glucosidase = acid maltase def)
3) Coris - type 3 (debranching enzyme = alpha-1,6-glucosidase def)
4) McArdles - type 4 (skeletal muscle glycogen phosphorylase def)
cardiomegaly and systemic findings leading to early death (by age 3) - which glycogen storage disease and what enzyme is deficient?
Pompe's = type 2
-lysosomal alpha-1,4-glucosidase (acid maltase)
severe fasting hypoglycemia, excessive glycogen in liver, increased blood lactate, hepatomegaly
Von Gierkes (type 1) = Glucose-6-Phosphatase deficiency (so can't do gluconeogenesis or glycogenolysis)
mild hypoglycemia, glycogen in liver, hepatomegaly, but normal blood lactate (because gluconeogenesis is intact)
Cori's disease = type 3 = debranching enzyme/alpha-1,6-glucosidase deficiency
painful muscle cramps, myoglobinuria with strenuous exercise - what glycogen storage disease?
mcardle's - type 5; skeletal muscle glycogen phosphorylase deficiency
--> have increased glycogen in muscle, but can't break it down.
--> does not affect longevity
Which lysosomal storage diseases are X-linked recessive? What are the rest?
Fabry's and Hunter's are X-linked recessive
The rest are Autosomal recessive
peripheral neuropathy of hands/feet, angiokeratomas, CV/renal disease, alpha-galactosidase A deficiency, ceramide trihexoside accumulation?
Fabry's disease (XR)
hepatosplenomegaly, aseptic necrosis of femur, bone crises, macrophages that look like crumpled tissue paper on microscopy, accumulation of glucocerebroside
cherry red spot on macula, foam cells on microscopy, neurodegeneration, hepatosplenomegaly, accumulation of sphingomyelin
Niemann-Pick disease ("No man picks his nose with his sphinger!)
cherry red spot on macula, lysosomes with onion skin, neurodegeneration, developmental delay, hexosaminidase A deficiency, GM2 ganglioside accumulation
Tay-Sachs (tay saX lacks heXoaminidase)
optic atrophy, globoid cells, neuropathy, development delay, galctocerebroside accumulation
ataxia and dementia, central and peripheral demyelination, cerebroside sulfate accumulation
corneal clouding, airway obstruction, gargoylism, hepatosplenomegaly, development delay; heparan sulfate and dermatan sulfate accumulation
aggressive behavior + mild symptoms of Hurler's syndrome (dev'l delay, gargoylism, airway obstruction, hepatosplenomegaly); heparan sulfate and dermatan sulfate accumulation
Hunter's syndrome (XR)
Hypoketotic hypoglycemia (+ weakness and hypotonia)
Carnitine deficiency: can't transport LCFAs into mitochondria, so get toxic accumulation in cytoplasm
how many kcal from 1 g protein, carb, fat?
1 g protein --> 4 kcal
1 g carb --> 4 kcal
1 g fat --> 9 kcal
LCAT = lecithin-cholesterol acyltransferase: what does it do?
takes cholesterol and puts it into HDL particles (catalyzes esterification of cholesterol)
CETP = cholesterol ester transfer protein: what does it do?
allows HDL to deposit cholesterol into LDL, etc.. (mediates transfer of cholesterol esters to other lipoprotein particles)
mediates VLDL and chylomicron remanant uptake by liver cells
activates LCAT (for cholesterol esterification)
lipoprotein lipase cofactor (LPL --> degrades TG circulating in chylomicrons and VLDLs)
mediates chylomicron secretion by the intestine and chylomicron assembly
binds LDL receptor (LDL particle uptake by extrahepatic cells)
familial dyslipidemia with increased chylomicrons, increased blood TG and cholesterol; pancreatitis, xanthomas...
type 1: hyper-chylomicronemia
-no increase risk for atherosclerosis
familial dyslipidemia with increased LDL; atherosclerosis, Achilles xanthomas, corneal arcus; elevated blood cholesterol
type IIa - familial hypercholesterolemia
-MI by age 20 if homozygous
familial dyslipidemia with increased VLDL; increased blood TGS; pancreatitis
type IV - hypertriglyceridemia
-have hepatic overproduction of VLDL