Other Information Exam 2 Flashcards
Cofactor
help a protein / enzyme catalyze a reaction
can be inorganic, organic, or permanently attached
What do we call permanently attached cofactors?
Prosthetic groups
What are types of inorganic cofactors?
metals, ions
What do we call organic cofactors?
coenzyme
What is alpha keratin’s quaternary structure determined by?
disulfide bonds
What does alpha keratin’s structure include?
apart from alpha helix secondary structure, lots of hydrophobic regions to promote packing
What is proline’s structure made of?
Gly-X-Y repeats to facilitate the left-handed helix
Why does proline use Gly and Pro?
Glycine gives flexibility and proline introduces a kink that can form a turn
How does proline’s structure come together?
there is a coiled coiled which is linked through covalent bonds
what is silk’s protein name?
fibroin
What amino acids do Beta sheets include? Why?
alacine and glycine
R-groups are small and can be stacked closely on top of each other
What two molecules regulate ATCase?
ATP and CTP
How does CTP regulate ATCase?
CTP is a product of ATCase, so it negatively regulates through feedback inhibition when concentrations are high enough
How does ATP regulate ATCase?
large concentrations of ATP indicate that metabolism is pumping and the cell might need to grow and need more products
so ATP positively regulates
Does ATCase show homotropic or hetereotropic inhibition?
It exihibits both!
How do ATP and CTP both regulate ATCase?
heterotropic regulation
How is ATCase regulated homotropically?
through a separate aspartate substrate binding?
is the Vmax of ATCase affected?
no
alpha+beta
easy to pick out regions of alpha and beta secondary structure
alpha/beta
hard to pick out regions of alpha and beta secondary structure
What are the highly hydrophobic side chains?
methionine, leucine, phenylalanine, and isoleucine
How do the H+ protons in a lower pH stabilize the T-state?
The H+ protons bind at histidine and make it positively charged
Histidine interacts with a negatively charged aspartate to stabilize the T-state
Additionally, H+ causes lots of histidines to be positively charged which creates large repulsion which triggers a conformational change into the T-state
How does CO2 stabilize the t-state?
besides lowering the pH, it also interacts with the amino terminus of the hemoglobin and forms a carbonyl group
How does BPG stabilize the t-state?
BPG is negatively charged and interacts with postively charged amino acids in the central portion of hemoglobin
this allows the subunits to be held in the T-state