B2.045 Molecular Mechanims for Regulating Metabolism Flashcards Preview

MCM Test 3 > B2.045 Molecular Mechanims for Regulating Metabolism > Flashcards

Flashcards in B2.045 Molecular Mechanims for Regulating Metabolism Deck (11)
Loading flashcards...

what are the 3 biological "stories" or regulation discussed?

1. isoform/tissue expression
2. allosteric regulation
3. post-translational trafficking and modification


how is GLUT4 localization regulated?

insulin stimulation and muscle contraction allow translocation of GLUT4 from vesicles to plasma membrane


discuss the relationship between ubiquitous GLUT1 tissue distribution and its value of Km=5ish

Km is similar to normal blood glucose concentrations allowing it to be effective across the range of normal glucose levels


relate the low Km=1.4 of GLUT3 to the high energy needs of the brain

this low Km allows glucose transport into the brain even in low glucose conditions because brain requires glucose as fuel even in starved state


what would be the effect of increasing GLUT4 concentration on the enzyme activity curve?

vmax would increase
km wouldn't change


how can kcat changes be visualized on an enzyme activity curve?

changes in vmax


what does sigmoidal shape tell you about an enzyme?

cooperativity is present, more than one ligand binding site


how is the insulin monomer formed?

initial mRNA codes for 110 AAs
AAs are cleaved and disulfide bridges form between two chains


what three forms can insulin take?

monomer, dimer, hexamer


what is the insulin hexamer?

inactive, storage form of insulin
bound to zinc ions for stability


what is the effect of recombinant insulin?

alters equilibrium between monomer-dimer-hexamer forms