Biomedical Engineering Reference
In-Depth Information
(a)
(c)
(b)
(d)
Dockerin 1
Cohesin 1
E1
E3
Dockerin 2
Cohesin 2
E2
Linker
Dockerin 3
Cohesin 3
Figure 15.3
Biotechnological.approaches.for.constructing.enzyme.complexes.for.substrate.channeling:.a.fusion.protein.with.
multiple. functions. (a),. an. enzyme. complex. through. the. linkage. of. scaffolding. (b),. coimmobilization. of. ran-
domly. mixed. enzyme. complexes. (c),. and. coimmobilization. of. positionally. assembled. enzyme. complexes. (d)..
(Reprinted.from.
Proteomics
,.11,.Zhang,.W.,.Zhao,.C.,.Wang,.S..et.al.,.Coating.cells.with.cationic.silica-magnetite.
nanocomposites.for.rapid.puriication.of.integral.plasma.membrane.proteins,.3482-3490,.Copyright.2011,.with.
permission.from.Elsevier.)
covered.electrode..The.tris(2,2-bipyridine).ruthenium(II).label.allowed.for.the.detection.of.
the.BSA.concentration.on.the.electrode.
15.3 Applications of Nanotechnology to Bioprocessing
15.3.1 enzymatic reactions
Enzymes. or. biological. catalysts. are. widely. used. for. a. variety. of. applications. including.
synthesis.of.pharmaceutical.intermediates,.production.of.food.products,.detergents,.and.
production.of.specialty.chemicals..Enzymes.are.able.to.catalyze.a.broad.range.of.chemi-
cal.reactions.including.hydrolysis,.oxidation,.reduction,.polymerization,.etc..In.addition,.
enzymes. are. able. to. work. under. mild. conditions. including. near. ambient. temperatures,.
neutral. pH. and. aqueous. environments,. making. them. highly. favored. for. “green”. chem-
istry.. Finally,. enzymes. exhibit. exquisite. speciicity. including. regio-. and. enantiomeric.
speciicity,.allowing.them.to.produce.chiral.compounds.with.high.yields.without.dificult.
puriication.processes..Despite.these.extensive.advantages,.enzymatic.biocatalysis.suffers.
from.some.signiicant.limitations..Enzymes.are.expensive,.unstable,.exhibit.poor.activity.
in.organic.solvents,.and.are.dificult.to.separate.from.the.chemical.reactions,.often.increas-
ing.the.puriication.costs..To.alleviate.many.of.these.issues,.enzymes.are.often.immobilized.
for. bioprocessing. applications. (Brady. and. Jordaan. 2009).. While. immobilized. enzymes.
