Lecture 21 Flashcards
(29 cards)
What two places are are proteins typically made?
1) cytosol on free ribosomes
2) inner cytoplasmic surface of the endoplasmic reticulum (lumen which is geographically outside of the cell)
What happens when the protein being translated is 70 amino acids long?
It protrudes from the ribosome and a ribonucleo protein particle recognizes the 15 - 20 hydrophobic amino acid sequence at the proteins N terminal and binds to it, ceasing elongation.
How do proteins make it known that they are destined for the lysosome?
There will be a mannose-6-phosphate residue attached to it enzymatically
What occurs in I-cell disease?
A genetic defect in adding mannose-6-phosphate to enzymes so signaling certain proteins to go to the lysosome is impaired.
due to inclusion bodies
Where are nuclear proteins made, what is their signaling, and what recognizes this signal?
- Free ribosomes
- basic amino acids
- importing and Ran proteins
How are proteins destined for the peroxisome targeted and who recognizes the targeting signal?
- they’re given a peroxisomal targeting sequence that is recognized by PTS receptors
What happens in Zellweger syndrome?
A defect in the peroxisomal targeting of proteins
Why is it important to remove sulfates from molecules and what is responsible for this?
- if not, consequence is progressive paralysis, skeletal deformities, and neurological defects.
- enzymes called sulfatases
what is multiple sulfates deficiency?
genetic disease with unmodified sulfatases
What is Keshan disease?
Disease where selenium is deficient, characterized by dilated cardiomyopathy striated muscle degeneration, and a flabby heart lol
- selenium is an essential micronutrient
What does glutathione peroxidase do and how?
Reduces peroxides by converting toxic R-OOH groups back to R-OH groups
What is the popular reducing agent used by glutathione peroxidase?
glutathione
What converts T4 to active T3?
5’-deiodinase
What does the K in vitamin K stand for?
coagulation
What does Warfarin (Coumadin) do?
Inhibitor that competes with vitamin K and reduces synthesis of clotting factors 2, 7, 9, 10
What is the signal for Mitochondrial targeting?
A-terminal leader 20-80 charged AA’s
Which amino acids do not have a Modification?
Gly, Ala, val, ile,leu
what is the Mechanism of a perm?
reduce the sulfide bonds, then oxidize the bonds back.
What are the sites that are usually phosphorylated?
ser, thr, tyr
phosphorylation of eIF2 results in what?
inhibition
Phosphorylation of eIF2 results in what?
inhibition
Phosphorylation of eIF4E results in what?
stimulation
Phosphorylation of 4E-BP results in what?
stimulation
What is the 21st amihe acid and. what is it’s codon?
SeCys and UGA
