CURRICULUM VITAE

NAME: Tomohiro HIRAISHI

EDUCATION: 1990-1994, Tokyo Institute of Technology,Department of Bioengineering 1994-1999, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology

DEGREES: Dr. Engineering, Tokyo Institute of Technology

APPOINTMENTS: 1999-2000: Special Postdoctoral Researcher, Polymer Chemistry Lab. (高分子化学研究室）, RIKEN 2000-2004: Researcher, Polymer Chemistry Lab.（高分子化学研究室）, RIKEN 2004-2008: Researcher, Bioengineering Laboratory （前田バイオ工学研究室）, RIKEN 2008- : Senior Research Scientist, Bioengineering Laboratory （前田バイオ工学研究室）, RIKEN 2006- : Lecturer, Tokyo Institute of Technology （東京工業大学・非常勤講師） 2007- : Associate professor, Tokyo Medical and Dental University （東京医科歯科大学・客員准教授） 2009- : Associate professor, Universiti Sains Malaysia （マレーシア科学大学・連携准教授）

ACADEMIC ACTIVITIES: Membership: The Society of Polymer Science, Japan

PUBLICATIONS (selected): 1) Hiraishi T, Komiya N, Matsumoto H, Abe H, Fujita M & Maeda M:Degradation and adsorption characteristics of PHB depolymerase

as revealed by kinetics for the mutant enzymes with amino acid substitution in substrate-binding domain, Biomacromolecules 11: 113-119, 2010

2) Hiraishi T, Masuda E, Miyamoto D, Kanayama N, Abe H, & Maeda M: Enzymatic synthesis of poly(α-ethyl β-aspartate) by polyethylene glycol-modified poly(aspartate) hydrolase-1, Macromol. Biosci., 2010, in press.

3) Hiraishi T, Masuda E, Nagata M, Kanayama N, Doi Y, Abe H & Maeda M: Cloning of poly(aspartic acid) (PAA) hydrolase-1 gene from Pedobacter sp. KP-2 and hydrolysis of thermally synthesized PAA by its gene product, Macromol. Biosci. 9: 10-19, 2009

4) Hiraishi T, Hirahara Y, Doi Y, Maeda M & Taguchi S: Effects of mutations in the substrate-binding domain of poly[(R)-3-hydoxybutyrate] (PHB) depolymerase from Ralstonia pickettii T1 on PHB degradation, Appl. Environ. Microbiol. 72: 7331-7338, 2006

5) Normi YM, Hiraishi T, Taguchi S, Abe H, Sudesh K, Nazalan N, & Doi Y: Characterization and properties of G4X mutants of Ralstonia eutropha PHA synthase for poly(3-hydroxybutyrate) biosynthesis in Escherichia coli., Macromol. Biosci. 5: 197-206, 2005

β-Peptide synthesis by β-peptide hydrolase

700 900 1100 1300 1500 1700 1900 21002000 1500 1000

n=15

m/z = 143n+46+23 MALDI-TOF MS

Enzymatic polymerization has great potential as an environmentally compatible process. We previously purified a novel β-peptide hydrolase from Pedobacter sp. KP-2. By taking advantages of the substrate recognition by this enzyme, we successfully synthesized β-poly(aspartic acid).

(R : Et, Me, etc.)

ROH

C O

R

(recognizes β,β-linkage)

NH2 OR OR

O

O

OR O

NH

O

β

O NH

O

β

OR

NH2 OR OR

O

O

PahZ1KP-2 22.533.544.55

δ (ppm) 5 4 3 2

1H NMR β-unit

(4.4 ppm) α-unit (4.6 ppm)

Adsorption

Hydrolysis

Biopolyester

Substrate-binding domain (SBD)

Catalytic domain

Linker region

10 nm

Interaction between biopolyester and amino acid residues in depolymerase

Depolymerase gene

Mutant library

Random mutagenesis

Screening and functional mapping

Enzymatic degradation of biopolyester begins with depolymerase adsorption to the polymer surface followed by the hydrolysis of biopolyester chains. We identified the residues involved in the interaction between them, and found that the hydrophobic interaction at these positions plays a crucial role in the enzyme adsorption.

Enzymatic synthesis and degradation of biopolymers

(Macromol. Biosci. 2009, 9, 10.: patent filing 2007-175275 )

(Appl. Environ. Microbiol. 2006, 72, 7331)