Transcript Enzymes

Biofuel Enzymes
A Study of Enzyme Kinetics
Speed up the rate of reactions
 Generally proteins
 Have active site in cleft of protein where
reactions take place
 The charges and positions of the R groups
(variable side chains) amino acids
critical for activity of enzyme.
 Active site is where reactants
Enzymes position
the substrate
(reactants) in such a
way as to lower the
energy needed for
the reaction to
Enzyme Factors
Changes in salinity affect side chains in active
Changes in pH affect side chains in active site
Temperature affects the activity of an enzyme
Relative concentration of both substrates and
enzymes affect the rate of reaction (Vmax).
Cellulosic Ethanol Production
Pretreat to remove non-cellulose biomolecules
such as lignin
Enzymatic Hydrolysis uses cellulases to produce
six carbon sugars such as glucose
Microbial fermentation converts sugars into
Cellulose vs Cellulase
Cellulose makes up cell wall in plants
Cellulose in form of cellulose microfibrils and
Cellulases break down cellulose into glucose
Animals do not make produce cellulases
Types of Cellulases
Endocellulases – break down internal bonds
within a long chain of glucose molecules
Exocellulases – break the bonds on the ends of
the cellulose to create two sugar cellobiose
Cellobiases- break the bonds in cellobiose to
make two glucose sugars
Studying Cellobiase
Can’t quantitatively detect presence of glucose
or absence of cellobiose
Use artificial substrate of p-nitrophenyl
glucopyranoside (PNPG)
When PNPG is cleaved by the cellobiase, it
produces p-nitrophenol. If you add a base to pnitrophenol, it will turn yellow.
The deepness of yellow color can be compared
visually or by spectrophotometry to produce
quantitative results
To study Enzyme Kinetics we will:
Determine the Rate of Reaction in the Presence or
Absence of an Enzyme
Determine the Effect of Temperature on the Reaction
Determine the Effect of pH on the Reaction Rate
Determine the Effect of Enzyme Concentration on
the Reaction Rate
Determine the Effect of Substrate Concentration of
Reaction Rate
Test the Ability of Mushroom Extracts to Increase
the Reaction Rate