Polymer Synthesis nd Modification Enzymatic Catalysis通过酶催化聚合物的合成和改性

1、polymer synthesis and modification by enzymatic catalysismuttaqin23 june 2009history overviewnenzymatic reactions have been widely used since 1980sntwo major directions of polymerization catalyst :nacids-bases ntransition metal nenzymatic polymerizationmotivationmotivationsynthesis and modification

2、of polymers using enzymatic catalysis for better performance and environmentoutlineoutlinenintroductionnhydrolase enzymesnenzymatic polymerizationnmodification of polymersnapplications ndisadvantages of the enzymatic methodnconclusionnreferencesintroduction :characteristics of enzymatic synthesisntw

3、o important aspects on enzymatic reactions :1.key and lock theory (fischer : 1894)introduction :characteristic of enzymatic synthesis2.lowering the activation energy (pauling)reaction profilekey factor :design and synthesisan artificial monomerintroduction :advantages of enzymatic polymerizationnpre

4、cise control of polymer structures (regioselectivity, chemoselectivity, stereochemistry)nno need protection and deprotectionnclean process, mild condition, environmental friendlynproduce biodegradable polymers (many cases) introduction :classification of enzymesenzymesexamples enzymestypical polymer

5、s-1typical polymers-21. oxidoreductaseperoxidasetyrosinaseglucose oxidasepolyphenols, polyanilines, vynyl polymerspolysaccharides, polypeptides (protein)2.transferaseglycosyltransferaseacyltransferasepolysaccharides, cyclic olygosaccharides, polyesterpolysaccharides, polypeptides (protein)3.hydrolas

6、eglycosidase (cellulase, chitinase, amylase, etc)lipasepeptidasepolysaccharides, polyester, polyamides, polycarbonates, poly(amino acid)spolysaccharides, polypeptides (protein)4. lyasedecarboxylaseadolase, dehydrasepolysaccharides5. isomeraseracemaseepimerase6. ligaseacyl coa synthetaseenzymatic pol

7、ymerization :hydrolase lipase enzymenlipase is an enzyme that catalyzes the hydrolysis of fatty acid esternlipase can be used to catalyse polymerization reactions, such as polyesternthe reaction of lipase-catalyzed polymerization can be done by rop or polycondensationenzymatic polymerization :reacti

8、on mechanism of ropenzymatic polymerization : reaction mechanism of ropthe rate determining step is the em formationenzymatic polymerization :polyester via polycondensationenzymatic polymerization :enantioselective and chemoselectivenenantioselective : -prefer to produce one enantiomer to anothernch

9、emoselective :-selective to a functional groupmodification of polymer :by enzymatic catalysisnpurposenimprove the polymer properties nproduce polymer with environmental friendlynfulfill market demandmodification of polymer :polysaccharides by lipase enzymeapplications :npolysaccharidesnbiocompatible

10、, biodegradable, and non-toxic use : biomedical purposes, such as for drug delivery. paper industries, water treatment, and other industrial applicationsapplications :npolyesterusefulness :packaging, textile, resin,liquid crystal display, plasticdisplay, etcdisadvantages of the enzymatic method1.lim

11、itation of substrates2.availability and cost of enzymes3.reaction : ofen slower than chemical methodsconclusionthe enzymatic reaction takes place under mild condition and is excellent in controlling polymer structuresthe enzymatic reaction also reduces environmental problemshowever, this reaction is

12、 restricted by availability of substrates and enzymesreferences1.macromolecule engineering. precise synthesis, material properties, application. edited by k. matyjaszewski, y. gnanou, and l. leiber. copyright 2007 wiley-vch verlag gmbh & co. kgaa, weinheim2.physical chemistry for the life sciences. p. atkins, j. d. paula. 2006 w.h. freeman and company