carbohydrates Flashcards
insulin will stimulate (3 things)
Protein synthesis, glycogen synthesis, triglyceride synthesis
what closes k+ channels and stimulates insulin release
sulfonylureas (e.g. glipizide, glyburide). used for type 2 diabetics.
GLUT1
red blood cell, brain endothelia cells; high affinity
GLUT2
Liver cells, pancreas cells; low affinity
GLUT3
neurons
GLUT4
fat, muscle, heart cells; insulin induced
GLUT5
testis; fructose transporter
Lactose
glucose + galactose
Sucrose
glucose + fructose
Maltose
glucose + glucose
fates of glucose-6-phosphate
- glycogen synth (glycogen)
- glycolysis (pyruvate–lactate and TCA)
- gluconeogenesis (phosphatase in liver) making glucose
- pentose phosphate pathway (ribose and NADPH)
glycogen phosphorylase
breaks off one glucose from glycogen and adds phosphate to it. contains pyridoxal phosphate (PLP) (cont pyridoxine B6)
von Gierke’s disease
Glycogen storage disorder; glucose-6 phosphatase; liver
within few months of birth severe hypoglycemia, epinephrine secretion -> stim fatty acid -> incr fatty acid prod in liver
McArdle’s disease
glycogen storage disorder; muscle glycogen phosphorylase; skeletal muscle
exercise induced cramps, muscle pain. typ diagnosed in 2nd to 3rd decade of life due to exercise intolerance
Herr’s disease
glycogen storage disease; liver glycogen phosphorylase; liver
precursors for glucose in gluconeogenesis
Lactate to pyruvate (lactate dehydrogenase),
alanine to pyruvate (alanine aminotransferase),
glycerol to dihydroxyacetone phosphate (DHAP but first through glycerol 3-phosphate)
pyruvate to phosphoenolpyruvate (PEP)
pyruvate to oxaloacetate with pyruvate carboxylase (mitochondia), oxaloacetate to phosphoenolpyruvate with phosphoenolpyruvate carboxykinase (PEPCK) (cytoplasm).
to get oxaloacetate out of mitochondria, convert to malate or aspartate in malate aspartate transfer thing
PPP isomerase
converts ribulase 5-phosphate to ribose 5-phosphate
PPP transketolase
transfers 2C keto units and is dependent on Thiamine (B1) by virtue of TPP
PPP transaldolase
transfers 3C keto units and uses lysine for nucleophilic attack on aldehyde (not tpp dep
these cause hemolytic anemia in G-6-P DH deficiency patients
sulfa drugs, antimalarials, antipyretics, certain infections, fava beans
fructosuria
fructokinase deficiency: benign
fructosemia
aldolase B deficiency: hypoglycemia
F-1-P inhib glyconenolysis (phosphorylase) and aldolase A, but aldo B can’t prod enough glycolysis
galactosemia
deficiency in galactose 1-P uridylytransferases. excess galactose appears in urine. results in cataracts and mental retardation.
galactose 1-P uridylytransferase moves UDP from UDP-gluc to galactose 1-P. (UDP-galactose converted to UDP-glucose by UDP-galactose-4-epimerase)
