The influence of fullerene on adsorption properties of silica gel with respect to peptides of middle molecular mass
E.Yu. Melenevskaya2, L.V. Sharonova3, L.N. Gall*, N.G. Podosenova1, and
A.S. Novikov1
1 Institute of Analytic Instrument Industry RAS, 190103 St.-Petersburg, Russia
2Institute of Macromolecular Compounds RAS, 199004 St.-Petersburg, Russia
3Ioffe Physico-Technical Institute RAS, 194021 St.Petersburg, Russia
Our recent studies of low-density lipoprotein (LDL) adsorption revealed the significant change in adsorption properties of silica gel and adsorption mechanism in the presence of C60 fullerene molecules. These results provide the possibility to use silica gel modified with fullerene for treatment and prophylaxis of atherosclerosis [1-3].
In this work we continue the investigation of selective adsorption of blood plasma components; it is aimed at obtaining adsorbent for efferent therapy at acute ischemic states of myocardium. The objects of adsorption were peptides with middle molecular mass, which appear in blood plasma in abundance at many pathological states. They are the products of protein degradation and act as secondary endotoxins, causing depressions and disorder of different physiological processes.
For the preparation of adsorbent we used amorphous silica gel MCA with pore diameter of 100 nm, specific surface equal to 150 m2/g, and total pore volume equal to 0.89 cm3/g ("Fullerene Technologies Ltd.", 99.5wt.% grade). Two methods of introduction of fullerene into ailica gel were compared: in solid and liquid phase. We studied solutions of peptides isolated from blood plasma after adsorption and desorption from adsorbent.
Optical absorption spectra were taken using spectrophotometer SF 2000, molecular masses of peptides were determined using mass-spectrometer MX 5303 equipped with electrospray ionization device and time-of-flight mass analyzer, connected with microcolumn liquid chromatograph.
Analysis of optical absorption spectra of peptides revealed the influence of fullerene and method of its introduction onto adsorption propeties of silica gel. It was shown that silica gels after solid-phase introduction of fullerene possess maximum adsorption capacity and specificity. The change in absorption binding of peptides with silica gel was observed. The role of chemoadsorption arises after solid-phase introduction of fullerene.
From the comparison of mass-spectra it was shown that during adsorption the formation of new peptides with low mass takes place, presumably as a result of sequencing of initial peptides.
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