Biochem Flashcards
Euchromatin vs heterochromatin
Euchromatin- transcribed (“truly transcribed”)
heterochromatin- condensed, transcriptionally active
What amino acids are histones rich in?
lysine and arginine- pos charged
What histone is not part of the nucleosome
H1
Histone methylation vs acetylation
Methylation- represses DAN transcription (“Mute”)
Acetylation- relaxes coiling, allowing for transcription (“Active”)
What are purines vs pyrimidnes?
Purines: A, G (2 rings)
Pyrimidines: C, T, U (1 ring)
What amino acids are necessary for purine synthesis?
GAG
Glycine
Aspartate
Glutamine
Which pathway is orotic acid involved in?
Pyrimidine base production
What pathways are carbamoyl phosphate involved in?
de novo pyrimidine synthesis
urea cycle
What does Leflunomide inhibit
dihydroorotate reductase (mitochondrial, pyrimidine)
What does mecophenolate inhibit?
IMP dehydrogenase (Purine-GMP prod)
What does ribavirin inhibit?
IMP dehdrogenase (purine-GMP prod)
What does hydroxyurea inhibit?
ribonucleotide reductase (UDP to dUDP)
What do 6-MP and azathioprine inhibit?
de novo purine synthesis
Adenoside deaminase deficiency
SCID
excess ATP and dATP
Hyperuricemia, gout, self-mutilation
Lesch-Nyhan
HGPRT (hypoxanthine to IMP, guanine to GMP)
Describe purine salvage?
GMP-Gunanine-Xanthine-Uric acid
AMP-IMP-Hypoxanthine-Xanthine-Uric acid
DNA pol I vs DNA pol III
DNA pol III- elongates leading and lagging strand (5’-3’ synth), proofreads with 3’-5’ exonuclease
DNA pol I- degrades RNA primer, replaces with DNA
What is a transition and transversion mutation?
Transition- purine to purine or pyrimidine to pyrimidine
Transversion- purine to pyrimidine etc
What is mutated in ataxia tenagiectasia?
repair of double stranded breaks
When is nucleotide excision repair vs base excision repair used?
nucleotide excision repair- bulky distortion (eg pyrimidine dimer)- done by specific endonucleases
base excision repair- altered base (eg deamination)
What enzymes are involved in base excision repair
Glycosylase removes base AP-endonuclease cleaves 5' end Lyase cleaves 3' end DNA polymerase b fins gape ligase seals
How are DNA, RNA and protein synthesized?
DNA, RNA: 5’-3’
Protein- N to C terminus
What do the RNA polymerases do?
RNA pol I: makes rRNA
RNA pol II: makes mRNA (opens DNA at promoter site
RNA pol III: makes tRNA
a-amanitin toxicity
inhibits RNA pol II
severe hepatotoxicity
How is RNA processed? where is this done?
5’ capped with methylguanosine
3’ polyadenylation
splicing out of introns
in nucleus
How are pre-mRNAs processed
snRNPs form lariat intermediate
What do the T-arm, D-arm, and stem of tRNAs do?
T-arm: binds to ribosome (thymine, pseudouridine, cytosine residue)
D-arm: allows for recognition of correct tRNA by aminoacyl tRNA synthetase
stem: 3’ CCA accepts amino acid
What are Nissl bodies?
RER in neurons
What modifications can RER make?
N-linked oligosaccharide to protein
What modifications can Golgi make?
N-oligosaccharide on asparagine
O-oligosaccharide on serine, threonine
What is the signal for trafficking to the lysosome?
mannose-6-phosphate
Course facial features, clouded corneas, restricted joint movement, high plasma levels lysosomal enzymes
I-cell disease
deficiency phosphotransferase
cant phosphorylate mannose residue- secreted extracellulary instead of to lysosome
What do the vesicular trafficking proteins indicate (COPI, COPII, clathrin)
COPI- retrograde golgi, Golgi to ER
COPII- anterograde golgi, ER to golgi
Clathrin- trans-golgi to lysosome; plasma membrane- endosome
What disease has proteasome defect been implicated in?
Parkinsons
Dynein vs kinesin
Dynein- retrograde (+ to -)
kinesin- anterograde
What is axonemal dynein do?
ATPase powers cilia bending
What is the molecular mechanism of digoxin?
inhibits NaKATPase
indirect inhibition of Na/Ca2+ exchainge, incr Ca2+, incr contractility
What is the most abundant protein in the human body
collagen
What do the different types of collagen do?
I: bone, skin, tendon, dentin, fascia, cornea, wound repair
II: cartilage, vitreous body, nucleus puplosus
III: skin, blood vessels, uterus, fetal tissue, granulation tissue
IV: basement membrane, basal lamina, lens
What types of collagen are mutated in Ehlers-Danlos?
Classic type (joint + skin)- mutation in type V collagen Vascular type (vascular, organ rupture)- deficiency in type III collagen
Brittle, kinky hair, growth retardation, hypotonia
Menkes disease
impaired copper absorption
decr activity lysyl oxidase
What is the most abundant amino acid in collagen
glycine
What modifications are made to collagen?
Inside fibroblast: hydroxylation of proline and lysine glycosylation of hydroxylysine Outside fibroblast: cleavage of disulfide-rich terminal regions and crosslinking (lysyl oxidase)
What amino acids make up elastin?
proline and glycine
What genetic disease typically shows mosaicism
mccune albright
Hyperphagia, obesity, intellectual disability, hypogonadism, hypotonia
Prader-Willi
Paternal gene is deleted or mutated (25% from maternal uniparental disomy) Chr 15
Inappropriate laughter, seizures, ataxia, severe intellectual disability
Angelman syndrome
Maternal gene is deleted or mutated (5% from paternal uniparental disomy) Chr 15
myopathy, lactic acidosis, CNS
ragged red fibers on muscle biopsy
mitochondrial myopathies
failure of ox phs
Vitamin-D resistant rickets
name and inheritance
Hypophosphatemic rickets
incr phosphate wasting in proximal tubule
Telangiectasia, recurrent epistaxis, skin discoloration, AVM, GI bleed, hematuria
Hereditary hemorrhagic telangiectasia
autosomal dominant
Inheritance of MEN
Aut dom
Colon covered with adenomatous polyps before puberty
Familial adenomatous polyposis
APC gene Ch 5
Aut DOm
cafe-au-lait spots and cutaneous neurofibromas
NF-1
Chr 17
Aut Dom- 100% penetrance, variable expressivity
bilateral acoustin schwannomas, juvenile cataracts, meningiomas, ependymomas
NF2
Chr 22
Aut Dom
Numerous benign hamartomas, multiple organ involvement
tuberous sclerosis
Aut Dom- incomplete penetrance, variable expressivity
What is the treatment for CF?
N-acetylcystein to loosen mucous plug Dornase alta (DNAse) to clear leukocytic debris
How is CF diagnosed?
Cl- in sweat >60mEq/L
Describe the physiology of CF?
Defect in ATP-gated Cl- channel
Cant secrete Cl- in lungs and gut and sweat
Incr intracellular Cl-
Incr compensatory excretion Na+ absorption and H20 absorption
thick mucus
Myotonia, muscle wasting, frontal balding, cataracts, testicular atrophy, arrythmia
Myotonic type 1 muscular dystrophy
CTG trinucleotide repeat of DMPK gene
Abnormal expression of myotonin protein kinase
Post-pubertal macroorchidism, long face with large jaw, large everted ears, autism, mitral valve prolapse
Fragile X
methylation and expression FMR1 gene
Trinucleotide repeat: CGC
What trinucleotide repeats cause Fragile X Friedreich ataxia Huntington Myotonic dystrophy
Fragile X- CGG
Friedreich- GAA
Hungtington-CAG
Myotonic dystroph- CTG
Severe intellectual disability, rocker-bottom feet, micrognathia, low-set ears, clenched hands, prominent occiput
Edwards, Trisomy 18
Severe intellectual disability, rocker-bottom feet, microphtalmia, microcephaly, cleft lip/palate, holoprosencephaly, polydactyly
Patau syndrome, trisomy 13
microcephaly, intellectual disability, high pitched crying, epicanthal folds, VSD
Cri-du-chat
microdeletion of short arm of chromosome 5
defect in DiGeorge or velocardiofacial
22q11 deletion
What vitamins are stored in the liver?
B12, folate
Often cause dermatitis, glossitis, diarrhea
Vit B deficiencies
Fat sol vitamins
ADEK
Another name for B1
thiamine, TPP
Another name for B2
riboflavin: FAD, FMN
Another name for B3
Niacin
Another name for B5
pantothenic acid: CoA
Another name for B6
pyridoxine: PLP
Another name for B7
biotin
Another name for B9
Folate
Another name for B12
Cobalamin
Night blindness, dry, scaly skin, alopecia, corneal degeneration, immune suppression
Vit A
prevents squamous metaplasia, component of retinal
How is diagnosis of thiamine deficiency made?
incr RBC transketolase activity after Vit B1 administration
Confusion, ophtalmoplegia, ataxia, confabulation, memory loss
Wernicke Korsakoof syndrome
Dry vs wet beriberi
Dry: polyneuritis, symmetrical muscle wasting
Wet: high output cardiac failure (dilated cardiomyopathy), edema
Cheilosis, corneal vascularization
Vit B2 deficiency (riboflavin)
Glossitis, diarrhea, dermatitis, dementia
Vit B3 (niacin) deficiency
What enzymes use thiamine? (4)
pyruvate dehydrogenase (links glyoclysis, TCA)
a-ketoglutarate dehydrogenace (TCA)
Transketolase (HMP shunt)
Branched-chain ketoacid dehydrogenase
Dermatitis, eneteritis, alopecia, adrenal insufficiency
Vit B5 (pantothenate) deficeincy
Convulsions, hyperiritability, peripheral neuropathy, sideroblastic anemia
Vit B6 (pyridoxine) deficiency
What reactions require pyridoxine? (3)
PLP- transamination, decarboxylation reactions, glycogen phosphorylase
What is vitamine B7 a coenzyme for?
carboxylation enzymes (eg pyrovate carboxylase, acetylCoA carboxylase, propionyl CoA carboxylase)
Macrocytic, megaloblastic anemia, hypersegmented PMNs, incr homocystein, normal methylmalonic CoA
Folic acid (B9) deficiency
Macrocytic, megaloblastic anemia,
paresthesias, subacute combined degeneration, hypersegmented PMNs, incr homocystein, incr methylmalonic CoA
B12 (cobalamin) deficiency
What important synthetic reactions is VitC involved in?
hydroxylation of proline and lysine- collagen synthesis
dopamine b-hydroxylase- converts dopamine to NE
Where is excess vitamin D likely?
sarcoidosis (incr activation of vit D by epithelioid macrophages)
Hemolytic anemia, acanthocytosis, muscle weakness, posterior column and spinocerebellar tract demyelination
Vit E deficiency
What reaction is vit K important for?
g-carboxylation of glutamic acid
Delayed wound healing, hypogonadism, decr adult hair, dysguesia, anosmia, acrodermatitis enteropathica
Zinc deficiency
What are the metabolic consequences of excess ethanol in the liver?
Incr NADH/NAD+ ratio
lactic acidosis
prevents gluconeogenesis- hypoglycemia (oxaloacetate-malate)
hepatosteatosis
Kwashiorkor vs Marasmus
Kwashiorkor- skin lesions, edema, liver malfunction (swollen belly- decr apolipoprotein synth)
Marasmus- tissue and muscle wasting, loss of subcut fat, variable edema
What 3 pathways take place in both the mitochondria and cytoplasm?
HUGs take two:
Heme synthesis
Urea cycle
Gluconeogenesis
What is the rate-determining step of glycolysis? What regulates it? (4)
Phosphofructokinase-1 (PFK-1)
AMP+, fructose-2,6-bisphospate+
ATP-, citrate-
What is the rate-determining step of gluconeogenesis? What regulates it? (4)
Fructose-1,6-bisphosphatase
ATP+, AcetylCoa+
AMP- fructose 2,6 bisphosphate-
What is the rate-determining step of the TCA cycle? What regulates it? (3)
Isocitrate dehydrogenase
ADP+
ATP-, NADH-
What is the rate-determining step of glycogenesis? What regulates it? (5)
Glycogen synthase
G6P+, insulin+, cortisol+
Epinephrine-, glucagon-
What is the rate-determining step of glycogenolysis? What regulates it? (6)
Glycogen phosphorylase
Epinephrine+, Glucagon+, AMP+
G6P-, insulin-, cortisol-
What is the rate-determining step of de novo pyrimidine synthesis?
Carbamoyl phosphate synthetase II
What is the rate-determining step of de novo purine synthesis?
Glutamine-PRPP amidotransferase
What is the rate-determining step of the urea cycle? What regulates it? (1)
Carbamoyl phosphate synthetase I
N-acetylgultamate+
What is the rate-determining step of fatty acid synthesis? What regulates it? (4)
Acetyl-CoA carboxylase (ACC)
insulin+, citrate+
glucagon-, palmitoyl-CoA-
What is the rate-determining step of fatty acid oxidation? What regulates it? (1)
carnitine acyltransferase I
Malonyl-Coa-
What is the rate-determining step of ketogenesis?
HMG-CoA synthase
What do hexokinase and glucokinase do?
Both convert glucose to glucose 6-P
Hexokinase- most tissues; sequesters glucose in tissues at low concentrations (low Km, Vmax(
glucokinase- liver only, under control of liver, no neg feedback by G6P; stores glucose in liver at high concentrations (high Km, Vmax)
Describe the use of NAD vs NADP
NAD+- used in catabolic processes
NADPH- used in anabolic processes (product of HMP shunt)
How is the amount of Fructose-2,6-bisphosphate regulated?
F26BP- favors glycolysis
FBPase-2 (promotes F6P) and PFK-2 (promotes F26BP) regulate
Fasting state- incr glucagon- PKA activtiy- incr FBPase2, decr PFK2– gluconeogenesis
fed state- incr insluin- decr PKA activity- decr FBPase2, incr PFK2— glycolysis
Vomiting, rice-water stools, garlic breath
arsenic poisoning
inhibition of lipoic acid
What does pyruvate dehydrogenase complex do?
links glycolysis and TCA cycle
pyruvate, NAD+, CoA– acetylCoa, CO2, NADH
What cofactors does pyruvate dehydrogenase complex require?
B1, B2, B3, B5, Lipoic acid
Neurologic defects, lactic acidosis, incr serum alanine
Pyruvate dehydrogenase complex deficiency
Treat with ketogenic nutrients (high fat, lysine, leucine)
What are the only purely ketogenic amino acids?
Lysine, leucine
What are the 4 possible metabolites of pyruvate?
Alanine (ALT, B6)
Oxaloacetate (pyruvate carboxylase, biotin)
AcetylCoA (pyruvate dehydrogenase)
Lactate (lactate dehydrogenase- b3)
Retonone
Inhibits Complex I
electron transport inhibitor
Cyanide
inhibits complex IV
electron transport inhibitor
Oligomycin
Inhibits complex V
ATP synthase inhibitor
2,4 dinitrophenol
uncoupling agent
illicit weight loss agent
What tissues can participate in gluconeogenesis? What enzyme is essential?
Mostly liver
also kidney, epithelium
muscle cant: no glucose-6-phosphate
Pyruvate decarboxylase
Where does it take place? what required?
gluconeogenesis
in mitochndria: pyruvate to oxaloacetate
Requires biotin, ATP; activated by acetylCoA
What fatty acids can contribute to gluconeogenesis?
only odd chain fatty acids (via succinyl CoA)
Phosphoenolpyruvate carboxykinase
How is it regulated? What does it do? Where?
oxaolacetate to PEP
in cytosol
requires GTP
regulated transcriptionally by glucagon, cortisol
What does glucose-6 phosphatase do? where?
Glucose-6-P to glucose
in ER of liver
deficient in von-geirke
What does the HMP shunt do?
Yields NADPH from Glucose-6-P, also ribose for nucleotide synthesis
What is the rate limiting stelp of HMP shunt
Glucose-6-P dehydrogenase
oxidative, irreversible
What is an important conezyme for HMP shunt pathway?
B1
nonoxidative, make G3P, F6P
What is the advantage of G6PD def?
incr malarial resistance
Fructose in blood and urine; relatively asymptomatic
essential fructosuria
defect in fructokinase (Fructose to Fructose-1-P)
Aut Rec
Hypoglycemia, faundice, cirrhosis, vomiting
reducing sugars in urine
Fructose intolerance
deficiency in aldolase B
Fructos1P to dihdryacteoneP, glcyeraldehyde
Decrease in phosphate- inhibition of glycogenolysis, gluconeogenesis
Infantile cataracts
galactose in blood and urine
galactokinase deficiency
Aut R
accumulation of galacticol
failure to thrive, jaundice, hepatomegaly, infantile cataracts, intellectual disability
classic galactosemia
defect in galactose-1-phosphate uridyltransferase
Aut R
accumulation galacticol, phosphate depletion
What cell types have aldose reductase and sorbitol dehydrogenase?
What cell types have only aldose reductase?
both: liver, ovaries, seminal vesicles
AR only: schann cells, retina, kidneys, lens
At risk for osmotic damage due to accum of sorbitol
Bloating, cramps, flatulence, osmotic diarrhea
decr pH stool, incr hydrogen content breath
lactase deficiency
What are the glucogenic aminoacids?
Methionine, valine, histidine
What are the acidic aminoacids? Charge at body pH?
aspartic acid, glutamic acid
negatively charged
What are the basic amino acids? What is the charge at body pH?
Arginine, lysine, histidine
Important part of histones
His has no charge
What do alterations in BUN levels indicate?
incr BUN- kidney dysfunction
decr BUN- liver dysfunction
What is an obligate cofactor of the urea cycle?
N-acetylgultamate
Req for carbamoyl phosphate synthesis
What reactions of the urea cycle take place in the mitochondria?
Carbamoyl phosphate synthetase I
Ornithine transcarbamylase
Tremor, slurring of speech somonlence, vomiting, cerebral edema, blurring of vision
Ammonia intoxicification
How is hyperammonia treated?
Benzoate or phenybutyrate (bind AA- secretion)
Lactulose- GI trap
Describe pathogenesis of hyperammonemia?
depletion of a-ketoglutarate (via NH4 excess)
inhibition of TCA cycle
What are the advantages/ disadvantages of alanine vs cori cycle? What do they both do?
Cori- regenerates NAD+
also causes acidosis
transports alananine and glutamate to liver
How is N-acetylglutamate deficiency distinguished from carbamoyl phosphate synthetase-1 deficiency?
both hyperammonemia
N-acetylglutamate: incr ornithine with normal urea cycle enzymes
Hyperammonemia, incr orotic acid in blood in urine, decr BUN
Ornithine transcarbamylase deficiency
Excess carbamoly phosphate converted to orotic acid
X-lined recessive
no megaloblastic anemia
What amino acid is melatonin derived from? What factors required?
Tryptophan
BH4, B6
What amino acid is niacin derived from?
trypotphan
What amino acids is serotonin derived from?
tryptophan
What amino acid are catecholamines derived from?
phenylalanine/tyrosine
What is GABA derived from?
glutamate
What is heme derived from?
glycine
What is histamine derived from?
histidine
Intellectual disability, growth retardation, seizures, fair skin, eczema, musty odor
phenylketonuria
What enzymes are derfective in PKU? What amino acid is now essential?
phenlyalanine hydroxylase
tetrahydrobiopterin cofactor
tyrosine essential
Dark connective tissue, brown pigmented sclerae, urine turns black when exposed to air, arthralgia
alkaptonuria
homogenistic oxidase deficiency
aut rec
involved in degredation of tyrosine to fumarate
incr homocysteine in urine, intellectual disability, osteoporosis, tall stature, kyphosis, lens subluxation, thrmobosis, atherosclerosis
homocystinuria
What enzymes can be defective in homocystinuria? What is treatment for each?
cystathionine deficiency- decr methionine, incr cysteine, incr B12 and folate in diet
Decr affinity of cystahione synthase for PLP: incr B6, incr cysteine
homocysteine methyltransferase deficiency: treat by incr methionine
Cyanide nitroprusside test is positive
cystinuria
Defect in cystinuria
hereditary defect of renal PCT and intestinal amino acid transporter
Cysteine, ornithine, lysine, arginine
Treatment of cystinuria
urine alkalization
chelating agents
severe CNS defects, intellectual disability, death, branched chain ketoacids in blood
maple syrup urine disease
decr a-ketoacid dehydrogenase
Treatment of maple syrup urine disease
restriction of leucine, isoleucine, valine in diet
thiamine supplementation
How are glycogen phosphorylase and glycogen synthase regulated?
Glycogen phosphorylase (makes glucose)
-inhibited by protein phosphatases that activated by insulin
-activated by glycogen phosphorylase kinase that activated by glucagone (via PKA), calcium (epinephrine)
Glycogen synthase
-activated by insulin tyrosine kinase
-inhibited by PKA
Describe the bonds in glycogen
Branches: a(1-6) bonds
Linkages: a(1-4) bonds
Describe the process of glycogen breakdown
glycogen phosphorylase removes glucose-1-P
when down to 4 (limit dextrin), 4-a-D-glucanotransferase (debranching enzyme) removes 3
a-1,60glucosidase cleaves of last of branch
severe fasting hypoglycemia, incr glycogen in liver, incr blood lactate, hepatomegaly
Von Gierke (type I) defect in glucose-6-phosphatase AR
cardiomyopathy, muscle weakness, early death
Pompe disease (type II) defect in lysosomal a-1,4-glucosidase AR
Fasting hypoglycemia, incr glycogen in liver, normal blood lactate, hepatomegaly
Cori disease (Type III) defect in debranching enzyme (a-1,6-glucosidase) AR
painful muscle cramps, myoglobinuria, arrythmia
McArdle disease (Type V)
myophosphorylase (glycogen phosphorylase)
AR
Peripheral neuropathy of hands and feet, angiokeratoma, cardiovascular and renal disease
Fabry
a-galactosidase-A def
accum ceramide trihexoside
XR
Hepatosplenomegaly, pancytopenia, bone crises, aseptic necrosis of bone, crumpled tissue paper macrophages
Gaucher
glucocerebrosidase
gucocerbroside accum
AR
Progressive neurodegeneration, hepatosplenomegaly, Cherry-red macula spot, foam cells
Neimann-Pick
sphingomyelinase
Sphingomelin accum
AR
Progressive neurodegeneration, developmental delay, no hepatomegaly, Cherry-red macula spot, lysosomes with onion skin
Tay Sachs
hexosaminidase A
GM2 ganglioside accum
AR
Peripheral neuropathy, developmental delay, optic atrophy, globoid cells
Krabbe disease
Galactocerbrocidase
Galactrocerebroside and psychosine accum
AR
Central and peripheral deymelination
ataxia, dementia
Metacrhomatic leukodystrophy
arylsulfatase A
cerebroside sulfate
AR
Developmental delay, gargoylism, airway obstruction, corneal clouding, hepatosplenomegaly
Hurler syndrome
a-L-iduronidase
heparan sulfate, dermatan sulfate
AR
Developmental delay, gargoylism, airway obstruction, hepatosplenomegaly, aggressive behavior
Hunter syndrome
iduronate sulfatase
heparan sulfate, dermatan sulfate
XR
Weakness, hypotonia, hypoketotic hypoglycemai
carnitine deficiency
inability to transport LCFAs to mitochondria
Decr dycarboxylic acids, decr glucose, decr ketones
acyl-CoA dehydrogenase deficiency
acetyl-CoA required for pyruvate carboxylase in gluconeogenesis
Why do alcoholics have incr production of ketone bodies
excess NADH shunts oxaloacetate to malate
How many calories in protein, carbohydrate, fat, alcohol?
Protein, carbohydrate: 4 cal
Fat: 9 cal
Alcohol: 7 cal
How long does each last? ATP Creatine phosphate anaerobic metabolism aerobic metabolism
ATP: 2 sec
Creat phosphate: 10 sec
Anaerobic metabolism: 1 min
Aerobic: plateaus 1 min
How long does it take to deplete glycogen stores?
1d
What to LPLs do?
degrade TG circulating in chylomicrons and VLDLs
found on vascular endothelial surface
What to hepatic lipases do?
degrade TG in IDL
What do hormone-sensitive lipases do?
degrad TG in adipocytes
What do LCAT and CETP do?
LCAT- esterification of cholesterol- helps for mature HDL
CETP- helps transfer cholesterol esters from HDL to other lipoproteins
esterified cholesterol is trapped in lipoprotein, cant diffuse across membrane
What does Apolipoprotein E do? Where is it found?
mediates remnant uptake
Found on all but LDL
What does Apolipoprotein A1 do? Where is it found?
activates LCAT (esterification of cholesterol) on chylomicron, HDL
What does Apolipoprotein C-II do? Where is it found?
cofactor for LPL
chylomicron, VLDL, HDL
What does Apolipoprotein B-48 do? Where is it found?
mediates chylomicron secretion
chylomicron, chylomicron remnant
What does Apolipoprotein B-100 do? Where is it found?
Binds LDLR
VLDL, IDL, LDL
What lipoproteins are highest in cholesterol? What do they do?
LDL and HDL
LDL transports chol from liver to tissues
HDL transports chol from tissue to liver
What does chylomicron do? what receptors?
delivers TGs to peripheral tissue (from intestinal)
delivers cholesterol to liver as chylomicron remant
E,A,C, B48 (all but B100)
What does VLDL do? what receptors?
delivers hepatic TGs to peripheral tissues (from liver)
E,C,B100
What does IDL do? what receptors?
degradation of VLDL, delivers TGs and cholesterol to liver
E, B100
What does LDL do? what receptors?
delivers hepatic cholesterol to peripheral tissue (formed in liver from IDL)
taken up via receptor-mediated endocytosis
B100 only
What does HDL do? what receptors?
mediates transport of cholesterol from periphery to liver
acts as repository for apoC and apoE
What lipoprotein is increase by alcohol?
HDL
pancreatitis, hepatosplenomegaly, pruritic xanthoams
I- hyperchylomicronemia
AR
lipoprotein lipase deficiency or altered lipoprotein C
accelerated atherosclerosis, tendon xanthomas, corneal arcus
IIa- familial hypercholesterolemia
Codominant/ autosomal dominant
absent or defective LDLR
pancreatitis, incr VLDL
IV- familial hypertriglycidemia
AD
