Flashcards in Test 23- BC Deck (47):
Glycogen degradation in skeletal muscle increases several hundred fold after the onset of contraction. This is due to enzyme activation by which substance?
What couples glycogen degradation to skeletal muscle contraction?
Calcium mediated myophosphorylase activation
Increased Ca in the cytosol activates phosphorylase kinase>
activates muscle phosphorylase
Maple syrup urine disease
defect in branched chain alpha ket acid DH>
inability to break down (LIV) beyond their deaminated alpha keto acid state>
elevated levels lead to neurotoxicity
Dystonia (sustained muscle contractions), poor feeding, maple syrup scent of urine
Tx for MSUD
restrict branched chain A
Krebs cycle mneumonic
is = isocitrate
krebs= alpha keto
starting= succinyl coa
Branched chain AA
Restrict in pts w/ PKU
Defective breakdown of tyrosine
What is the major AA responsible for transferring N to the liver for disposal?
What happens to amino groups during protein catabolism?
Transferred to alpha ketoglutarate to form GLUTAMATE
What happens to glutamate generated from catabolism of proteins?
Glutamate is processed in the liver to form urea which is disposed of
malate, citrate, OAA
intermediates of TCA cycle
AA produced as intermediate in conversion of ornithine to arginosuccinate during urea sycle
What forms calactitol?
excess circulating galactose in galactosemia by Aldose reductase
converts UDP galactose to UDP glucose
UDP galactose 4 epimerase
Beta galctosidase def
leads to accumulation of glycosaminoglycans (keratin sulfate in lysosomes)
def in aldolase B
hereditary frustose inolerance
Glucose 6 phosphatase
Converts glu-6 phosphate to glucose
*last step in production of glucose from gluconeogenesis or glycogenolysis
AA w/ three titratable H
vit that helps w/ treatment of measles
direction of DNA synthesis
5' to 3'
Activates trypsinogen to trypsin
most important enzyme for digestion of TG
condition that causes lipase def and leads to poor fat absorption and steatorrhea
activates pepsinogen to pepsin
acidic pH and small amt of pre-existing pepsin
hydrolyzes complex carbs to oligo, di and monosaccharides
secreted in response to LOW duodenal pH
stimulates bicarb secretion form pancrease and gallbladder>
reduced gastrin secretion/stomach acid
Sxs of vit deficiency years after dietary abscence.
can ONLY occur with vit B12
Enzymes in heme biosynthesis pathway inactivated by lead
zinc contaiing gamm-aminolevulinate dehydratase and ferrochelatase
What accumulates in lead poisoning?
protoporphyrin IX accumulate>
How does lead poisoning cause anemia?
inhibition of enzymes in heme pathway>
decreased production of heme>
microcytic anemia d/t a lack of Hb
Rate limiting step in heme synthesis that uses B6 and is inhibited by increased heme levels
Defect in porphogilinogen deaminase
Acute intermittent porphyria
Acute attacks of abdominal pain and neuropsychiatrix sxs
Urine is dark on exposure to light
Acute intermittent porphyria
Defect in uroporphyrinogen decarboxylase
porphyria cutanea tarda
Ab to citrullinated peptides
Antibodies to DS DNA
Autoantibodies that target Fc portion of human IgG
nonspecific for connective tissue disorders
SLE and antiphospholipid syndrome
DNA dep RNA polymerase that incorporates short RNA primers into replicating DNA
synthesizes daughter DNA strands
replaces RNA primers w/ DNA segments
Cofactor for synthesis of tyrosine, dopa and 5HT