aktivitas enzym
TRANSCRIPT
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Enzyme activity
How fast an enzyme is workingRate of Reaction
Rate of Reaction= Amount of substrate changed (or amount product formed in a given period of time.
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In most cases actua! mo!ar enzymeconcentration is not known. "e measureamount of enzyme by its activity in terms
of enzyme unit of rateor a I#. I# is a!so a way to monitor the enzyme
puri$cation.
In our study the enzyme activity wemeasure is more re!ated to amount ofenzyme rather than its physio!ogica!situation.
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I#
%ne I# is de$ned as the amount ofenzyme that produces a &mo!eproduct per minute under de$ned
conditions.
'he concentration of enzyme isepressed as I#m*
'he speci$c activity (+A) is thenumber of I# per mg protein. As the enzyme is puri$ed the +A
increases
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,ate
of,eaction
Enzyme activity
-ariab!e you are !ooking at
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Enzyme activity
our -ariab!es
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Enzyme activity
our -ariab!es
Temperature
pH
Enzyme Concentration
Substrate Concentration
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,ate
of,eaction
Temperature
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,ate
of,eaction
Temperature
/ 0/ 1/ 2/3/ 4/ 5/
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,ate
of,eaction
Temperature
/ 0/ 1/ 2/3/ 4/ 5/
4/o6 7 denatures
27 4/o6Increase in Activity
82o6 7 inactive
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'emperature and Enzyme Activity Enzymesare most active at an optimum temperature
(usua!!y 19:6 in humans)
'hey show !itt!e activity at !ow temperatures Activity is !ost at high temperatures as denaturation
occurs
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E;ect of heat on enzyme activty
f you heat the protein above its optimal temperature
bonds breakaning the protein !oses it secondary and tertiary structure
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E;ect of heat on enzyme activty
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E;ect of heat on enzyme activty
E+ +HA?E+% +#@+',A'E % *%>E, I'+
ven if temperature !owered enzyme canBt regain its correct shap
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,ate
of,
eaction
pH
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,ate
of,
eaction
pH
3 1 40 2 5 9 C D
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,ate
of,
eaction
pH
3 1 40 2 5 9 C D
arrow pH optima
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,ate
of,
eaction
pH
3 1 40 2 5 9 C D
arrow pH optima
WHY?
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,ate
of,
eaction
pH
3 1 40 2 5 9 C D
arrow pH optima
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pH and Enzyme Activity
Enzymesare most active at optimum pH Amino acids with acidic or basic side7chains
have the proper charges when the pH isoptimum
Activity is !ost at !ow or high pH as tertiarystructure is disrupted
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%ptimum pH for +e!ected Enzymes
ost enzymes of the body have an optimum pHof about 9.4
However in certain organs enzymes operate at!ower and higher optimum pH va!ues
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,ate
of,
eaction
Enzyme Concentration
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,ate
of,
eaction
Enzyme Concentration
Enzyme 6oncentration
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Enzyme 6oncentration and ,eaction ,ate
'he rate of reaction increases as enzymeconcentration increases (at constant substrate
concentration) At higher enzyme concentrations more enzymes
are avai!ab!e to cata!yze the reaction (morereactions at once)
'here is a !inear re!ationship between reactionrate and enzyme concentration (at constantsubstrate concentration)
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,ate
of,
eaction
Substrate Concentration
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,ate
of,
eaction
Substrate Concentration
+ubstrate 6oncentration
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,ate
of,
eaction
Substrate Concentration
+ubstrate 6oncentration
Active sites fu!!7 maimum turnover