Control of enzymatic activity using thermosensitive polymers

Toshifumi Shiroya, Mamoru Yasui, Keiji Fujimoto, Haruma Kawaguchi

Research output: Contribution to journalArticle

41 Citations (Scopus)

Abstract

Carboxylated poly(N-isopropylacrylamide) (pNIPAM) was prepared in ethyl alcohol at 70°C by radical polymerization using 4,4′-azobis(N,N′-cyanopentanoic acid) (V-501) as the initiator. Trypsin was conjugated to carboxylated pNIPAM using carbodiimide and the pNIPAM-trypsin conjugate was subsequently fractionated by gel filtration. The lower critical solution temperature (LCST) of the pNIPAM-trypsin conjugates changed with the molecular weight of the coupled pNIPAM. The enzymatic activity of the conjugate and its temperature dependence was affected by both the molecular weight and the amount of the coupled pNIPAM. The relative activity of the conjugates decreased above the LCST, and one of the reasons for this could be a decrease in the diffusion of the substrate upon shrinkage of the coupled pNIPAM above the LCST. The enzymatic activity changed reversibly with temperature when the conjugates contained a certain amount of pNIPAM. In addition, the conjugates were more resistant against heat treatment than native trypsin. Circular dichroism measurements indicated that the tertiary structure of the conjugates was different from that of native trypsin.

Original languageEnglish
Pages (from-to)275-285
Number of pages11
JournalColloids and Surfaces B: Biointerfaces
Volume4
Issue number5
DOIs
Publication statusPublished - 1995 Jun 23

Fingerprint

trypsin
Polymers
Trypsin
polymers
Temperature
Molecular weight
molecular weight
Dichroism
Free radical polymerization
Molecular Weight
temperature
Carbodiimides
Ethanol
Thermodynamic properties
Gels
initiators
Heat treatment
poly-N-isopropylacrylamide
shrinkage
dichroism

Keywords

  • Enzymatic activity
  • Lower critical solution temperature
  • Poly(N-isopropylacrylamide)
  • Trypsin

ASJC Scopus subject areas

  • Biotechnology
  • Colloid and Surface Chemistry
  • Physical and Theoretical Chemistry
  • Surfaces and Interfaces

Cite this

Control of enzymatic activity using thermosensitive polymers. / Shiroya, Toshifumi; Yasui, Mamoru; Fujimoto, Keiji; Kawaguchi, Haruma.

In: Colloids and Surfaces B: Biointerfaces, Vol. 4, No. 5, 23.06.1995, p. 275-285.

Research output: Contribution to journalArticle

Shiroya, Toshifumi ; Yasui, Mamoru ; Fujimoto, Keiji ; Kawaguchi, Haruma. / Control of enzymatic activity using thermosensitive polymers. In: Colloids and Surfaces B: Biointerfaces. 1995 ; Vol. 4, No. 5. pp. 275-285.
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