Transcript Enzymes: “Helper” Protein molecules

Enzymes:
“Helper” Protein molecules
Regents Biology
Flow of energy through life
 Life is built on chemical reactions
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Chemical reactions of life
 Processes of life

building molecules
 synthesis

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breaking down molecules
 digestion
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Nothing works without enzymes!
 How important are enzymes?

all chemical reactions in living
organisms require enzymes to work
 building molecules
 synthesis enzymes
enzyme
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 breaking down molecules
 digestive enzymes
We can’t live
without enzymes!

enzymes speed up reactions
 “catalysts”
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enzyme
+
Examples
 synthesis
+
enzyme
 digestion
enzyme
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Examples
 dehydration synthesis (synthesis)
enzyme
 hydrolysis (digestion)
enzyme
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Enzymes are proteins
 Each enzyme is the specific helper to
a specific reaction
each enzyme needs to be the right shape
for the job
 enzymes are named for the reaction
they help

Oh, I get it!
They end
in -ase
 sucrase breaks down sucrose
 proteases breakdown proteins
 lipases breakdown lipids
 DNA polymerase builds DNA
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Enzyme vocabulary
 Enzyme

helper protein molecule
 Substrate

molecule that enzymes work on
 Products

what the enzyme helps produce from
the reaction
 Active site

part of enzyme
that substrate
molecule fits into
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Enzymes aren’t used up
 Enzymes are not changed by the reaction
used only temporarily
 re-used again for the same reaction with
other molecules
 very little enzyme needed to help in many
reactions

substrate
active site
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product
enzyme
It’s shape that matters!
 Lock & Key model

shape of protein
allows enzyme &
substrate to fit

specific enzyme
for each specific
reaction
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Factors that Affect Enzymes
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Factors Affecting Enzyme Function
 Enzyme concentration
 Substrate concentration
 Temperature
 pH
 Salinity
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catalase
Enzyme concentration
reaction rate
What’s
happening here?!
enzyme concentration
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Factors affecting enzyme function
 Enzyme concentration

as  enzyme =  reaction rate
 more enzymes = more frequently collide with
substrate

reaction rate levels off
reaction rate
 substrate becomes limiting factor
 not all enzyme molecules can find substrate
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enzyme concentration
Substrate concentration
reaction rate
What’s
happening here?!
substrate concentration
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Factors affecting enzyme function
 Substrate concentration

as  substrate =  reaction rate
 more substrate = more frequently collide with
enzyme

reaction rate levels off
reaction rate
 all enzymes have active site engaged
 enzyme is saturated
 maximum rate of reaction
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substrate concentration
Temperature
reaction rate
What’s
happening here?!
37°
temperature
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Factors affecting enzyme function
 Temperature

Optimum T°
 greatest number of molecular collisions
 human enzymes = 35°- 40°C
 body temp = 37°C

Heat: increase beyond optimum T°
 increased energy level of molecules disrupts
bonds in enzyme & between enzyme & substrate
 H, ionic = weak bonds
 denaturation = lose 3D shape (3° structure)

Cold: decrease T°
 molecules move slower
 decrease collisions between enzyme & substrate
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Enzymes and temperature
 Different enzymes function in different
organisms in different environments
reaction rate
human enzyme
hot spring
bacteria enzyme
37°C
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temperature
70°C
(158°F)
How do ectotherms do it?
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pH
What’s
happening here?!
trypsin
reaction rate
pepsin
pepsin
trypsin
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pH
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Factors affecting enzyme function
 pH

changes in pH
 adds or remove H+
 disrupts bonds, disrupts 3D shape
 disrupts attractions between charged amino acids
 affect 2° & 3° structure
 denatures protein

optimal pH?
 most human enzymes = pH 6-8
 depends on localized conditions
 pepsin (stomach) = pH 2-3
 trypsin (small intestines) = pH 8
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Salinity
reaction rate
What’s
happening here?!
salt concentration
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Factors affecting enzyme function
 Salt concentration

changes in salinity
 adds or removes cations (+) & anions (–)
 disrupts bonds, disrupts 3D shape
 disrupts attractions between charged amino acids
 affect 2° & 3° structure
 denatures protein

enzymes intolerant of extreme salinity
 Dead Sea is called dead for a reason!
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For enzymes…
What matters?
SHAPE!
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2009-2010
 Title: LAB 2: Factors Affecting Enzyme Activity
 Introduction: (What is the purpose of this lab?)
 Lab Report

4 sections
 Title: (ex: Enzyme Concentration)
 Introduction: Purpose of this specific experiment/what is your
hypothesis?
 Results and Data: (Data table and graph)
 Conclusion (Explain your results, was your hypothesis
supported, sources of error/improvement)

Questions (1-4)
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