Lecture 13&14: Post translational modifications

Question 1

Protein function is controlled by

Answer 1

post translational modifications

Question 2

proteasome

Answer 2

degrade protein with a poly-ubiquitination modification in the cytosol

Question 3

How are proteins modified with ubiquitin?

Answer 3

1. E1 ubiquitin activating enzyme (ATP dependent)
2. E2 ubiquitin conjugating enzyme
3. E3 ubiquitin ligase transfer ubiquitin to substrate and make a ubiquitin chain structure

substrate; modified target proteins
dub: remove ubiquitin

Question 4

phosphorylation status of a protein is determined by

Answer 4

kinases phosphatases

Question 5

phosphorylation (reversible)

Answer 5

-transient addition of PO4- to protein by kinase
-removed by phosphatase
-regulate protein conformation, interaction, localization

Question 6

cells differ in

Answer 6

morphology and function

Question 7

cell size order

Answer 7

bacterium<yeast cell<mammalian cell< oocyte