Immobilize Enzyme System Flashcards
The restriction of enzyme mobility in a fixed space is known as ______. This provides important advantages,
such as enzyme reutilization and elimination of enzyme recovery and purification processes, and may provide a better environment for enzyme activity.
Enzyme Immobilization
Since enzymes are expensive,
this is critical for many
processes.
Catalyst-reuse
is the physical enclosure of enzymes in a small space.
Entrapment
Major methods of Entrapment
Matrix entrapment and Membrane entrapment
used for enzyme immobilization are usually
polymeric materials such as Ca-alginate, agar, k-carrageenin, polyacrylamide, and collagen. However, some solid such as activated carbon, porous ceramic, and diatomaceous earth can also be
used for this purpose.
Matrices
it can be a particle, a
membrane, or a fiber.
Matrix
is either extruded or a template is used to shape the particles from a liquid polymer-enzyme mixture.
Polymerized gel-containing enzyme
entrapment of enzymes
is possible; for example, hollow
fiber units have been used to
entrap an enzyme solution
between thin, semipermeable
membranes.
Membrane Entrapment
A special form of membrane
entrapment is _______. In this technique, microscopic
hollow spheres are farmed. The
spheres contain the enzyme
solution, while the sphere is
enclosed within a porous
membrane. The membrane can be polymeric or an enriched
interfacial phase formed around a microdrop.
Microencapsulation
can be overcome by reducing the MW cutoff of membranes or the pore size of solid matrices.
Enzyme Leakage
can be eliminated by reducing the particle size of matrices and/or capsules.
Diffusion Limitation
are due to unfavorable
microenvironmental conditions,
which are difficult to control.
However, by using different
matrices and chemical ingredients, by changing processing conditions, and by reducing particle or capsule size, more favorable microenvironmental conditions can be obtained.
Reduced enzyme activity and
stability
is usually less significant in microcapsules as compared to gel beads.
Diffusion Barrier
The two major types of
immobilizations of enzymes on the surfaces of support materials are
Adsorption and Covalent Binding
is the attachment of
enzymes on the surfaces of support particles by weak physical forces, such as van der Waals or dispersion forces
Adsorption
is a common problem, especially in the presence of strong hydrodynamic forces, since binding forces are weak.
desorption of enzymes
The _______ of the adsorbed
enzyme is usually unaffected, and nearly full activity is retained upon adsorption.
Active Site
Adsorption of enzymes may be
stabilized by cross-linking with “blank”. “Blank” treatment can denature some proteins.
Glutaraldehyde
is the retention of enzymes on support surfaces by covalent bond formation.
Covalent Binding
Enzyme molecules bind to support material via certain “blank”, such as amino, carboxyl, hydroxyl, and sulfhydryl groups.
functional groups
These functional groups must not be in the
Active Site
Functional groups on support
material are usually activated by using “blank”, such as
cyanogen bromide, carbodiimide, and glutaraldehyde.
Chemical Reagent
One common trick Is to block the active site by flooding the enzyme solution with a “blank” prior to covalent binding.
Competitive Inhibitor
This may cause significant changes in the active
site of enzymes, and also severe diffusion limitations may result.
Cross-linking
