PMID- 17407341
OWN - NLM
STAT- MEDLINE
DCOM- 20070925
LR  - 20131121
IS  - 1520-6106 (Print)
IS  - 1520-5207 (Linking)
VI  - 111
IP  - 29
DP  - 2007 Jul 26
TI  - Immobilization of hexokinase onto chitosan decorated particles.
PG  - 8520-6
AB  - Chitosan (CH) decorated polystyrene (PS) particles were synthesized within 
      complexes of CH, a polycation under acid conditions, and tiny amounts of sodium 
      dodecylsulfate (SDS). Particle characterization was performed by means of dynamic 
      light scattering, zeta potential measurements, and transmission electron 
      microscopy. All dispersions were stable in the ionic strength of 2.0 mol L-1 NaCl 
      during 2 months. The outstanding colloidal stability was attributed to the 
      presence of a hydrated CH layer around the particles. CH decorated PS particles 
      were attached to atomic force microscopy cantilevers and probed against Si wafers 
      in water and in NaCl 0.01 mol/L. The mean thickness of CH layer amounted to 35 
      +/- 11 and 16 +/- 6 nm, when the medium was water and NaCl 0.01 mol/L, 
      respectively. Adsorption isotherm of hexokinase (HK) onto PS/CH particles studied 
      by means of spectrophotometry showed three regions: an initial step; adsorption 
      plateau and multilayer formation. Enzymatic activity of free HK and immobilized 
      HK was monitored by means of spectrophotometry as a function of storing time and 
      reuse. After 3 days, storing HK free in solution dramatically lost its catalytic 
      properties. On the contrary, HK-covered PS/CH particles retained enzymatic 
      activity over 1 month. Moreover, HK-covered PS/CH particles could be reused in 
      the determination of glucose two times consecutively, without losing activity. 
      These interesting findings were discussed in light of the role of water in enzyme 
      conformation.
FAU - Castro, Lizandra B R
AU  - Castro LB
AD  - Instituto de Quimica, Universidade de Sao Paulo, P. O. Box 26077, Sao Paulo, SP, 
      05513-970, Brazil.
FAU - Silva, Fabio F
AU  - Silva FF
FAU - Carmona-Ribeiro, Ana M
AU  - Carmona-Ribeiro AM
FAU - Kappl, Michael
AU  - Kappl M
FAU - Petri, Denise F S
AU  - Petri DF
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20070404
PL  - United States
TA  - J Phys Chem B
JT  - The journal of physical chemistry. B
JID - 101157530
RN  - 0 (Colloids)
RN  - 0 (Enzymes, Immobilized)
RN  - 0 (Polystyrenes)
RN  - 059QF0KO0R (Water)
RN  - 368GB5141J (Sodium Dodecyl Sulfate)
RN  - 9012-76-4 (Chitosan)
RN  - EC 2.7.1.1 (Hexokinase)
SB  - IM
MH  - Chitosan/*chemistry
MH  - Colloids/chemistry
MH  - Enzymes, Immobilized/*chemistry
MH  - Hexokinase/*chemistry
MH  - *Microspheres
MH  - Polystyrenes/*chemistry
MH  - Protein Conformation
MH  - Sodium Dodecyl Sulfate/chemistry
MH  - Spectrum Analysis
MH  - Water/chemistry
EDAT- 2007/04/05 09:00
MHDA- 2007/09/26 09:00
CRDT- 2007/04/05 09:00
PHST- 2007/04/05 09:00 [pubmed]
PHST- 2007/09/26 09:00 [medline]
PHST- 2007/04/05 09:00 [entrez]
AID - 10.1021/jp0686543 [doi]
PST - ppublish
SO  - J Phys Chem B. 2007 Jul 26;111(29):8520-6. doi: 10.1021/jp0686543. Epub 2007 Apr 
      4.