Enzymes, Drug Dosage, & Chemotherapy Medical Lab 05
Name(s): Period:
4
Date:
Il/t(/lc
'Background Enzymes
Catalysts are substance'sthat can rate of a reaction withoutbeing change the altered in the Process. EnzymeSare macromolecules that are biological catalysts. All enzymes are proteinsbut not all proteins are enzymes. Thed<.tiVdfiOfit enerᎎ)f a reaction is the amount of energy it takes to start a reaction-the amount of energy it takes to break the bonds of the reactant molecules. Enzymes speed up reactions by lowering the activation energy of the reaction-but without changing the free energy change of the reaction.
Activationenergy (EA) without enzyme
Activationenergy (EA)
g
withenzyme Energy of reactants
Change in free energy Energy of products
aSVÄ$rqte The active site is the part of the
substrate.The enzyme and the substrats foiq a complex called an is generally held together by weak inf@actions.The substrate is then converted into products, and the products are released from the enzyme.
enzyme that binds to
tau_enzynid O Substrates enteractive sä&;enzyme changes shape so its active site
@Substrates held in active site by weak
embraces the substrates (induced fit).
interactions,such as hydrogen bonds and ionic bonds.
Substrates
and speed up a reaction by
complex
• acting as a templatefor substrate • stressing the substrate(S and stabilizing the
OActive site is available for
transitionstate, • providing a favorable
two new substrate
molecules.
microenvironment, • participating directly in the cata lytic reaction.
Enzyme
O
Pro.ducts are
Products Copynght
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dramatically
affected by changes in the and pH and
de141P&R
temperature. Changes in the
precise shape of an enzyme usually mean the
be as effective.
Products.
Cummings
enzpus 00
shapesthat are by
enzyme will not
Substrates are Converted into
Released.
three
-dimensional
O Active site (and R groups of its amino acids) can lowerEx
Enzyme-substrate
The activity of an enzyme can be affected by D severalfactors.3Shapeu Enzyme have complicated
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