Lecture 14 Flashcards
Substrate level control
acts on a single reaction
Feedback control
targets a different step in the pathway
Activators
promote more products
Inhibitors
prevent more products
Isozymes
“Mix and match” subunits
catalyze the same reaction but with different efficiencies
tissue specificity
compartmentalized isozymes
development
temporal expression of isozymes
Reversible covalent modifications
- add functional group[s] to activate or inactivate enzyme
- post-translational modifications create nonproteinogenic AA
Kinases
add phosphates
Phosphatases
remove phosphates
What does the name of a kinase mean?
it indicates which AA the phosphate will be added to
Allostery
allosteric binding does not occur at active site
can still inhibit or promote reaction
CTP Binding
prefers T/inactive state
ATP Binding
prefers R/active state
Protein Synthesis Regulation
ON/OFF switch
two levels of control:
-transc reg at promoters
-transl reg at UTRs
Histones:
- Acetylation
- Phosphorylation
- Methylation
control transcription
- promotes transc
- prevents transc
- promotes or prevents transc
Proteolytic Activation
irreversible covalent modification
Zymogen
inactive form of
Proteolytic Activation of Chymotrypsin
active vs inactive
affects both primary and secondary structure
Common covalent modification
Lipid: myrisitc acid and farnesyl
Nut acids: adp ribose
Protein: ubiquitin
Carbs: greatest source of diversity
