Adsorption behavior and activity of horseradish peroxidase onto polysaccharide-decorated particles.
The adsorption behavior of horseradish peroxidase (HRP) onto hybrid particles of poly(methylmethacrylate) (PMMA) and carboxymethylcellulose (CMC) was investigated by means of spectrophotometry. Dispersions of PMMA/CMC particles were characterized by light scattering, zeta potential measurements and scanning electron microscopy before and after HRP adsorption. HRP adsorbed irreversibly onto PMMA/CMC particles; the adsorption isotherm showed an initial step and an adsorption plateau. The enzymatic activity of free HRP and immobilized HRP (plateau region) was monitored by means of spectrophotometry as a function of storing time. Upon adsorbing HRP there is little (up to 20%) or no reduction of enzymatic activity in comparison to that observed for free HRP in solution. After storing free HRP and HRP-covered PMMA/CMC particles for 18 days the level of enzymatic activity is kept. HRP-covered PMMA/CMC particles dispersions, which were dried and re-dispersed, retained 50% of their catalytic properties. These interesting findings were discussed in the light of a beneficial effect of a hydrated microenvironment for maintenance of enzyme conformation and activity.
Silva
Rubens Araujo
RA
Instituto de Química, Universidade de São Paulo, P.O. Box 26077, São Paulo, SP 05513-970, Brazil.
Carmona-Ribeiro
Ana M
AM
Petri
Denise Freitas Siqueira
DF
D000327:Adsorption; D002266:Carboxymethylcellulose Sodium / Q000737:chemistry*; D002384:Catalysis; D004800:Enzymes, Immobilized / Q000737:chemistry; D006735:Horseradish Peroxidase / Q000378:metabolism* / Q000493:pharmacokinetics*; D008027:Light; D008855:Microscopy, Electron, Scanning; D010084:Oxidation-Reduction; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry*; D012542:Scattering, Radiation; D013056:Spectrophotometry, Ultraviolet; D013997:Time Factors
D004800:Enzymes, Immobilized; D011134:Polysaccharides; D019904:Polymethyl Methacrylate; D006735:Horseradish Peroxidase; D002266:Carboxymethylcellulose Sodium