Aktivitas Enzym

7/23/2019 Aktivitas Enzym

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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+ +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



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,ate

of,

eaction


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



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,ate

of,

eaction


+ubstrate 6oncentration


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,ate

of,

eaction


+ubstrate 6oncentration

Active sites fu!!7 maimum turnover

Aktivitas Enzym

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