Silica protein-bound

A- Teflon Block B- Teflon Tubing (0.762-mm-o.d. and 0.305-ram-i.d.) C- Teflon-coated Fused Silica Capillary (367-flm-o.d. and 100- im-i.d.) D- Protein-bound Membrane E- Sample vial for collecting the Products... 

A new technique, known as material-enhanced laser desorption/ionization (MELDI), has become available for profiling proteins in complex mixtures [67], It uses derivatized carrier materials, such as cellulose, silica, poly(glycidyl methylacrylate/divinylbenzene), or diamond powder, to bind proteins from the sample. The carrier particles are derivatized with iminodiacetic acid (IDA) and loaded with ions to form [carrier-IDA-Cu +] complex, which is then added to the protein sample. The protein-bound carrier materials are spotted on the MALDI target, mixed with a MALDI matrix and analyzed by MALDI-TOF-MS. 

An increase in protein-bound silica was found in the blood plasma (trichloroacetic acid precipitate)... 

The interaction of polysilicic acids with polysaccharides appears to be an open field for investigation. There may be some common factor, as further evidenced by the finding that in the serum of silicotic patients there is an increase in mucoproteins and protein-bound hexoses, along with higher level of silica (248). Some association of polysaccharides with silica has probably existed since life began because in a primitive organism such as the diatom, when silica is deficient the cells become coated with a polyuronide of glucuronic residues (42), and no doubt the microporous silica skeleton is interpenetrated by this polymer. 

Morrissey 53) used transmission infrared spectroscopy to study protein adsorption onto silica particles in a heavy water (DzO) buffer. By observing the shift in the amide I absorption band, he could deduce the fraction of protein carbonyl groups involved in bonding to the silica surface. He found that bovine IgG had a bound fraction of 0.20 at low bulk solution concentrations, but only about 0.02 at high solution concentrations. However, neither prothrombin nor bovine serum albumin exhibited a change in bound fraction with concentration. Parallel experiments with flat silica plates using ellipsometry showed that the IgG-adsorbed layers had an optical thickness of 140 A and a surface concentration of 1.7 mg/m2 at low bulk solution concentration — in concentrated solutions the surface amount was 3.4 mg/m2 with a thickness of 320 A (Fig. 17). 

Figure 2.9 Hydrophobic-interaction chromatography of proteins. (A) Ammonium sulfate gradient from 2.16 to 0 M (B) ammonium sulfate and tetrabutylammonium bromide gradients from 2.16 to 0 M and from 0 to 10 mM, respectively (C) ammonium sulfate and tetrabutylammonium bromide gradients from 2.16 to 0 M and from 0 to 20 mM, respectively (D) ammonium sulfate and tetrabutylammonium bromide gradients from 2.16 to 0 M and from 0 to 40 mM, respectively. Chromatography conditions column, silica-bound polyether, 10 cm x 4.6 mm I.D. temperature, 25°C flow rate, 1 ml/min gradient, linear for 30 min background buffer, 50 mM phosphate, pH 6.5. Peaks a, cytochrome c b, ribonuclease A c, /3-lactoglobulin A d, lysozyme e, ovalbumin f, a-chymotrypsinogen A g, fetuin. (Reprinted from Ref. 45 with permission.)...

S. Allenmark, B. Bomgren, and H. Boren, Direct liquid chromatographic separation of enantiomers on immobilized protein stationary phases III. Optical resolution of a series of A-aroyl d, 1-amino acids by high-performance liquid chromatography onbovine serum albumin covalently bound to silica, /. Chromatogr. 264 (1983), 63-68. 

J. Haginaka and H. Takehira, Separation of enantiomers on a chiral stationary phase based on ovoglycoprotein. I. Influence of the pore size of base silica materials and bound protein amounts on chiral resolution, J. Chromatogr. 773 (1997), 85. 

The use of a convective macroporous polymer as an alternative support material instead of silica for the preparation of protein-based CSPs has successfully been demonstrated by Hofstetter et al. [221]. Enantioseparation was performed using a polymeric flow-through-type chromatographic support (POROS-EP, 20 pm polymer particles with epoxy functionalities) and covalently bound BSA as chiral SO. Using flow rates of up to 10 ml/min, rapid enantiomer separation of acidic compounds, including a variety of amino acid derivatives and drugs, could be achieved within a few minutes at medium efficiencies, typical for protein chiral stationary phases (Fig. 9.13). 

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