These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Enzymatic activity of cholesterol oxidase immobilized onto polymer nanoparticles mediated by Congo red.
    Author: Silva RA, Carmona-Ribeiro AM, Petri DF.
    Journal: Colloids Surf B Biointerfaces; 2013 Oct 01; 110():347-55. PubMed ID: 23751415.
    Abstract:
    Poly(ethylene glycol), PEG, decorated polystyrene (PS) nanoparticles were synthesized and characterized by means of dynamic light scattering (DLS), zeta (ζ) potential measurements, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The adsorption of Congo red (CR) onto PS/PEG particles was evidenced by the decrease of ζ potential values and increase in the particles mean diameter in comparison to bare particles. Cholesterol oxidase (ChOx), the main enzyme in the oxidation of cholesterol, adsorbed onto PS/PEG and PS/PEG/CR particles, as revealed by the increase in the particles mean size and spectrophotometry. The enzymatic activity of free and immobilized ChOx was determined as a function of time by means of a coupled reaction with horseradish peroxidase. The activity of free ChOx decreased with time, while the activity of immobilized ChOx increased with time; after 1h reaction the latter was half of the former. Freeze-drying the ChOx covered PS/PEG/CR particles allowed their storage for at least one month under room conditions without loss of enzymatic activity. Conjugation effects between CR and ChOx or cholesterol evidenced by circular dichroism and spectrophotometry rendered a conformational state of ChOx, such that the enzymatic action was favored. ChOx adsorbed onto PS/PEG presents no enzymatic activity, probably due to ChOx denaturation or unfavorable orientation. Freeze-dried and freshly prepared dispersions of ChOx immobilized onto PS/PEG/CR particles yielded linear response in the cholesterol concentration range of 100mgdL(-1) (lowest limit of normal blood concentration) to 300mgdL(-1) (high risk level).
    [Abstract] [Full Text] [Related] [New Search]