Lecture 13 & 14 (Exam 2) Flashcards
What are the 3 kinetics trends that are possible?
Linear
Hyperbolic
Sigmoidal
Metabolic enzymes are regulated by —
– __________ - different locations
– Enzyme _________ - on/off switch
– Enzyme _________ - volume control
– ________ signals and second messengers - master regulators
Compartmentalization
Concentration
Activity
Hormone
The HOW – Basic outcomes
- ________-level control acts on a single reaction.
- ________ control targets a different step in the pathway.
Substrate
Feedback
The HOW – Basic outcomes
- Activators (PROMOTE/PREVENT) more products
- Inhibitors (PROMOTE/PREVENT) more products
Promote
Prevent
The WHO – Isozymes
Called _____ and _____ subunits.
Mix and match
________ catalyze the same reaction but with different efficiencies. Have different amino acid sequences.
Isozymes
The WHAT – Reversible covalent modifications
- Add 1+ “functional groups” to activate/inactivate the enzyme.
- Post-translational modifications create _________ amino acids.
Nonproteinogenic
***See Lecture 14 Slide 7
What are some common lipid reversible covalent modifications?
Myristic acid
Farnesyl
What are common nucleic acid reversible covalent modifications?
ADP-ribose
What are common protein reversible covalent modifications?
Ubiquitin
In reversible covalent modifications, __________ provide the greatest source of diversity to the proteome.
Carbohydrates
Carbohydrates provide many modifications by –
1) ____ vs. ____ linkages
2) Composition of _______
3) Branched vs. Unbranched
4) _______ of oligosaccharide
O-
N-
Sugars
Length
This small molecule reversible covalent modification occurs when adding a carboxyl group.
y-carboxylation (Carboxyl added to gamma carbon)
This small molecule reversible covalent modification occurs when adding a sulfate group.
Sulfation
This small molecule reversible covalent modification occurs when adding an acetyl group.
Acetylation
This small molecule reversible covalent modification occurs when adding a phosphate group.
Phosphorylation
The enzymes catalyzing phosphorylation reactions are called…
Protein kinases
These are what reverse the effects of kinases by catalyzing the removal of phosphoric groups attached to proteins.
Protein phosphatases
Note: The name of a kinase indicates on which _____ _____ the phosphate will be added.
Amino acid
Why is phosphorylation activating?
1) __________: ATP hydrolysis can drive unfavorable reactions (Delta G = -50 kJ/mol)
2) _________: Physiological processes dictate reaction rate
3) Cell processes: ATP amounts dictated by metabolism (energy change) - Signal transduction amplification (catalytic turnover)
4) Shape and charge complementarity: Each phosphate adds (-2) charge and (3+) H-bonds
Thermodynamics
Kinetics
Why is phosphorylation activating?
1) __________: ATP hydrolysis can drive unfavorable reactions (Delta G = -50 kJ/mol)
2) _________: Physiological processes dictate reaction rate
3) Cell processes: ATP amounts dictated by metabolism (energy change) - Signal transduction amplification (catalytic turnover)
4) Shape and charge complementarity: Each phosphate adds (-2) charge and (3+) H-bonds
Thermodynamics
Kinetics
The WHERE – Allostery
Allosteric binding does NOT occur at the ______ _____.
Active site
Homoallostery occurs when the binding of one substrate favors binding of additional substrates, which is called ________.
Cooperativity
In _________, the kinetics of an enzyme can be controlled by separate substances. (i.e., ACTase with CTP and ATP)
Heteroallostery
