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*Enzymes as targets for mutation and change - Coggle Diagram
*Enzymes as targets for mutation and change
Basic properties of all catalysts are the same
They increase reaction rate (reactivity)
The have NO effect on reaction equilibrium constant
Effects of mutation on catalysis
Most mutations have no effect on catalysis
Loss of essential catalytic residues = complete loss of enzymatic function
conservative changes of essential catalytic residues are NOT well tolerated
Effects of many mutations are not yet discovered
Examples of what mutations can chance
Michaelis Constan (Km)t:
Mut decrease Km = increase enzyme activity
Mut increase Km = decreased enzyme activity
Maximal Velocity (Vmax):
Increase Vmax = increase enzyme activity
decrease Vmax = decrease enzyme activity
Examples
Muts can alter drug susceptibility
Chronic Myelogenous Leukemia (CML)
Translocation which codes for an abnormal protein - Bcr-Abl oncokinase
Increased tyrosine kinase activity - causes increased cell motility
Relapse occurs when mutations cause drug resistance
Amino acid deletions - Very bad!
Cystic Fibrosis
Alteration of CFTR protein which is supposed to transport Cl which helps to reduce mucus in the lungs of CF patients
One phenylalanine is lost due to mutation and that causes the enzyme to change
Mutations alter enzyme performance
Isozymes are examples of different proteins catalyzing the same reactions in order to adjust for different circumstances - thanks to mutations
Glucokinase (regulated by diurnal signals) and Hexokinase
Fix jet lag by cramming carbs for breakfast when you shift to the other timezone
Some isozymes are highly useful in clinical diagnosis
Creatine kinase w/ M and H subunits
M is more abundant in skeletal muscle
H is more abundant in cardiac tissue
Looking at the amount of H CPK in circulation can help to determine how severe an MI has been due to death and necrosis of cardiac tissue following MI
*Isozymes