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Tanaka, Hirokazu*; Koizumi, Satoshi; Hashimoto, Takeji; Kurosaki, Kazuhiro*; Kobayashi, Shiro*
Macromolecules, 40(17), p.6304 - 6315, 2007/08
Times Cited Count：30 Percentile：65.97(Polymer Science)We have investigated the self-assembling process of cellulose artificially synthesized via enzymatic polymerization as one of general problems of non-equilibrium phenomenon and pattern formation. The chemical reaction and the self-assembling process were explored at real time and in-situ by a combined small-angle neutron scattering (SANS), small-angle X-ray scattering (SAXS), ultra-SANS and ultra-SAXS method, together with wide-angle X-ray diffraction and field-emission scanning electron microscopy. The results revealed for the first time the following pieces of new evidence: (1) The enzymes (cellulase) as a catalyst aggregate themselves into associations; (2) Cellulose molecules created at each active site of enzymes associate themselves around the enzyme associations into cellulose aggregates having surface fractal dimensions Ds, increasing from 2 to 2.3 with reaction time. (3) The fractal structure formed at the end of the reaction extends over a surprisingly wide length scale ranging from 30 nm to 30 
m (3 orders of magnitude).
Tanaka, Hirokazu; Koizumi, Satoshi; Hashimoto, Takeji; Kurosaki, Kazuhiro*; Omae, Masashi*; Kobayashi, Shiro*
Physica B; Condensed Matter, 385-386(1), p.814 - 817, 2006/11
Times Cited Count：3 Percentile：17.95(Physics, Condensed Matter)We have investigated a self-assembling process of cellulose artificially synthesized via enzymatic polymerization by means of in-situ and time-resolved small-angle neutron scattering (SANS). The results elucidated the following: (1) cellulose molecules were synthesized at a special reaction site of the enzyme (cellulase) located on or near the smooth surface of the self-assembled enzymes formed in the reaction medium; (2) the synthesized molecules associated themselves via diffusion-limited aggregation (DLA) and crystallized into fibrils and (3) the fibrils formed the aggregates, which had the surface fractal dimension D
increasing from 2 to 2.3 with the reaction time, on the smooth surface of the enzyme aggregates.
Hashimoto, Takeji; Tanaka, Hirokazu*; Koizumi, Satoshi; Kurosaki, Kazuhiro*; Kobayashi, Shiro*
Bussei Kenkyu, 87(1), p.18 - 19, 2006/10
In this work we prepared separately two stable solutions A and B, as will be detailed below. Mixing the two solutions provides energy required for the enzymatic polymerization reaction and the reaction-induced self-assembly. In this sense our system is considered to belong to an open non-equilibrium system. We especially focus on self-assembling processes, mechanisms, and structures in mesoscopic scale, because they have not been well explored, despites its general importance for understanding pattern formation in nature, including biological systems.
Hashimoto, Takeji; Tanaka, Hirokazu; Koizumi, Satoshi; Kurosaki, Kazuhiro*; Omae, Masashi*; Kobayashi, Shiro*
Biomacromolecules, 7(9), p.2479 - 2482, 2006/09
Times Cited Count：13 Percentile：38.26(Biochemistry & Molecular Biology)no abstracts in English
Hashimoto, Takeji; Tanaka, Hirokazu; Koizumi, Satoshi; Kurosaki, Kazuhiro*; Omae, Masashi*; Kobayashi, Shiro*
no journal, ,
We have investigated self-assembling process of cellulose artificially synthesized via enzymatic polymerization by means of in-situ and time-resolved SANS (Small-angle Neutron Scattering). The results elucidated the followings: (1) Cellulose molecules synthesized at a special reaction site of the enzyme (cellulase) located on or near the smooth surface of self-assembled enzymes formed in the reaction medium; (2) The synthesized molecules associated themselves via DLA (diffusion-limited association) and crystallized into fibrils; (3) The fibrils formed the aggregates, which had surface fractal dimension Ds increasing from 2 to 2.3 with the reaction time, on the smooth surface of the enzyme aggregates.
