Enzymatic synthesis of novel polymer materials


Polymer thin film is prepared as a functional membrane on the substrate surface of a biosensor to measure the interaction between the membrane and molecules. Poly(aspartic acid), which has functional carboxyl groups, shows high biocompatibility and biodegradability. We are studying the enzymatic synthesis of poly(aspartic acid) with well-controlled structure.



Schematic representation of enzymatic synthesis and degradation.





T. Hiraishi, Y. Hirahara, Y. Doi, M. Maeda, and S. Taguchi, gEffects of mutations in the substrate-binding domain of poly[(R)-3-hydoxybutyrate] (PHB) depolymerase from Ralstonia pickettii T1 on PHB degradationh, Appl. Environ. Microbiol., 72, 7331-7338 i2006j


Y. M. Normi, T. Hiraishi, S. Taguchi, H. Abe, K. Sudesh, N. Najimudin, Y. Doi, gCharacterization and Properties of G4X Mutants of Ralstonia eutropha PHA synthase for Poly(3-hydroxybutyrate) Biosynthesis in Escherichia coli.h, Macromol. Biosci., 5, 197-206 (2005)


Y. M. Normi, T. Hiraishi, S. Taguchi, K. Sudesh, N. Najimudin, Y. Doi, gSite-directed Saturation Mutagenesis at Residue F420 and Recombination with Another Beneficial Mutation of Ralstonia eutropha PHA synthase.h, Biotechnol. Lett., 27, 705-712 (2005)


Y. Kikkawa, K. Yamashita, T. Hiraishi, M. Kanesato, Y. Doi, gAdsorption Behavior of Poly(3-hydroxybutyrate) Depolymerase on Polyester Surface Investigated by QCM and AFM.h, Biomacromolecules, 6, 2084-2090 (2005)


T. Hiraishi, Y. Kikkawa, M. Fujita, N. M. Yahaya, M. Kanesato, T. Tsuge, K. Sudesh, M. Maeda, Y. Doi, gAFM Observation of In Vitro Polymerized Poly[(R)-3-hydroxybutyrate] : Insight into Possible Mechanism of PHB Granule Formation.h, Biomacromolecules, 6, 2671-2677 (2005)


Y. Kikkawa, M. Narike, T. Hiraishi, M. Kanesato, K. Sudesh, Y. Doi, T. Tsuge, gOrganization of Polyhydroxyalkanoate Synthase for In Vitro Polymerization as Revealed by Atomic Force Microscopy.h, Macromol. Biosci., 5, 929-935 (2005)


T. Hiraishi, and Y. Doi, gEnzymatic degradation of poly(aspartic acid) catalyzed by its hydrolases.h, Bio Industry, 22, 43-50 (2005)


T. Hiraishi, M. Kajiyama, I. Yamato, and Y. Doi. gEnzymatic Hydrolysis of a- and b-Oligo(L-aspartic acid)s by Poly(aspartic acid) Hydrolases-1 and 2 from Sphingomonas sp. KT-1,h Macromol. Biosci., 4, 330-339 (2004)


T. Hiraishi, M. Kajiyama, K. Tabata, H. Abe, I. Yamato, and Y. Doi, gBiochemical and Molecular Characterization of Poly(aspartic acid) Hydrolase-2 from Sphingomonas sp. KT-1.h Biomacromolecules, 4, 1285-1292 (2003)


T. Hiraishi, M. Kajiyama, K. Tabata, I. Yamato, and Y. Doi, gGenetic Analysis and Characterization of Poly(aspartic acid) Hydrolase from Sphingomonas sp. KT-1.h Biomacromolecules, 4, 80-86 (2003)


T. Hiraishi, K. Tabata, and Y. Doi, gMicrobial and Enzymatic Hydrolysis of Poly(aspartic acid).h RIKEN Review, 42, 81-84 (2001)


K. Tabata, M. Kajiyama, T. Hiraishi, H. Abe, I. Yamato, and Y. Doi, gFunction and characterization of poly(aspartic acid) hydrolase from Sphingomonas sp. KT-1.h, Biomacromolecules, 2, 1155-1160 (2001)