enzymes
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what is an enzyme
globular protein can be regulated reaction specificity
what are ribozymes
have no protein but are catalytic RNA molecules
what is a cofactor usually what is it
non protein component needed for activity CHANGES PROTEIN SHAPE an ion of some sort
what is a co enzyme what are some examples
produced by vitamin take part in reaction but don’t alter the shape of a enzyme FAD, NAD+
what is a prosthetic group
a co factor that doesn’t alter group but is attached closely and is needed to function
all enzymes end in
-ase
what do enzymes do
acceleration towards reaction equilibrium lower the activation energy
what is the best shape for an active site
the shape is complementary to the transition complex lock and key is a load of bollocks
how do enzymes reduce activation energy
desolvation - single out substrate from solution induced fit entropy reduction
what happens if you add more substrate
a higher initial reaction rate and more product
what is the initially reaction velocity called
V0
when do you reach Vmax
when you have saturated all enzymes with substrate
do you ever reach Vmax
not really
what dose a larger Km indicate
a less stable enzyme substrate complex
what dose a smaller Km value indicate
a more stable enzyme substrate complex
what is Km
the substrate concentration to reach 1/2 Vmax
so what dose Vmax tell us Km tell us
Vmax - fast - higher the better Km - fit - the higher the number the less the affinity - faster
what the two Isozymes that catalyse glucose + ATP = glucose-6-phospahte
glucokinase hexokinase
where is glucokinase located
in the liver
where is the hexokinase located
everywhere else in the body
what are the properties of glucokinase
high Km high Vmax
what are the properties of hexokinase
low Km low Vmax
what happens after you eat a meal and blood glucose goes up
hexokinase activity doesn’t respond however glucokinase responds PORPORTIONATLLY to blood glucose
what happens when blood glucose is low
gluconeogenis realsease glucose from liver but glucokinase cant phosphorolate the glucose due to its high Km