Regulation Of Protein Activity Flashcards
How do allosteric inhibitors work?
They bind more tightly to the T state and therefore increase the proportion of the molecules in T state and therefore inhibit positive cooperativity
How do allosteric activators work?
First substrate molecule has difficultly binding but when it binds it causes a conformational change and at least 1 subunit –> R state
Allosteric Activators and inhibitors of phosphofructokinase
Activators = AMP,fructose-2,6-bisphosphate Inhibitors = citrate, ATP and H+
Describe covalent modification
Many different types of protein can be attached covalently to proteins via AAs
Most important type of covalent modification and enzymes involved
Phosphorylation = kinase
Dephosphorylation = phosphatase
How are phosphate groups added?
Phosphate groups can be added to the OH groups of serine, threonine or tyrosine
Why do phosphate groups causes a difference ?
Introduction of a bulky charged group can significantly affect enzyme conformation or substrate binding
Enzymes released as inactive precursors are called…
Zymogens
What does Proteolytic cleavage allow?
Inactive forms of enzymes to be transported safely to sites of action without causing premature Proteolytic cleavage
2 forms of long term regulation of enzyme regulation
1) regulation of enzyme synthesis by either in/decreasing rate of transcription of mRNA
2) regulated protein degradation.
Proteins destined for destruction are activated by addition of what?
Ubiquitin
3 ways of regulating metabolic pathways
1) feedback inhibition
2) feed forward activation
3) counter regulation of pathways
What are the intrinsic and extrinsic pathways activated by?
In = factor XII Ex = factor III
Main factor in the BCC?
Factor X
Classic haemophilia is caused by ?
Defect in factor XIII
