Activity of enzymes immobilized on microspheres with thermosensitive hairs

Mamoru Yasui, Toshifumi Shiroya, Keiji Fujimoto, Haruma Kawaguchi

研究成果: Article査読

65 被引用数 (Scopus)


Poly (N-isopropylacrylamide)s (PNIPAMs) carboxylated at one chain end or both ends were prepared by polymerization using 4,4,-azobis(N,N,-cyanopentanoic acid) (V-501) as an initiator and β-mercaptopropionic acid (MPA) as a chain transfer reagent. One end group of PNIPAM carboxylated at both ends was conjugated with latex particles, and another with trypsin using carbodiimide. Differential scanning calorimetry (DSC) revealed that PNIPAM on the particles exhibited a drastic phase transition, and that the transition temperature was largely elevated when the enzyme was immobilized at the chain end. Therefore, PNIPAM on the particles showed two phase transitions because of the coexistence of the enzyme-conjugated and non-conjugated PNIPAMs. The activity of trypsin immobilized on the particles with the PNIPAM spacer showed significant temperature dependence. The apparent relative activity increased above the transition temperature of non enzyme-conjugated PNIPAM on the particles. One of the reasons for this is that the diffusion of the substrate changed discontinuously around the transition temperature. Therefore, the temperature dependence of the enzymatic activity was significantly affected by the molecular size of the substrates. The enzymatic activity was also influenced by the surface density of trypsin and PNIPAM on the particle, and the molecular weight of the PNIPAM spacer.

ジャーナルColloids and Surfaces B: Biointerfaces
出版ステータスPublished - 1997 5月 10

ASJC Scopus subject areas

  • バイオテクノロジー
  • 表面および界面
  • 物理化学および理論化学
  • コロイド化学および表面化学


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