On cellulose powder

To obtain individual sialic acids in pure, or almost pure, form, the sialic acid mixture obtained from the procedures just described are subjected to partition chromatography on cellulose powder, using, as the solvent,74107 1 2 1 (v/v/v) 1 -butanol-l-propanol-water. The (less hydrophilic) tri- and di-O-acetylated sialic acids are eluted first, followed by mono-O-acetylated sialic acids, NeuoAc, and Neu5Gc, ac-... 

Electrophoretic Methods. Several electrophoretic procedures have been developed to fractionate or purify the various caseins (McKenzie 1971C Thompson 1971 Whitney 1977). Wake and Baldwin (1961) fractionated whole casein by zone electrophoresis on cellulose powder in 7 M urea and 0.02 ionic strength sodium phosphate buffer at pH 7 and 5°C. Payens and co-workers employed several somewhat different electrophoretic conditions for the fractionation and purification of the caseins on cellulose columns (Payens 1961 Schmidt and Payens 1963 Schmidt 1967). Three fractions, as-, k-, and /3-caseins, were separated at pH 7.5 and 30°C with 4.6 M urea-barbiturate buffer. The purification of asi-casein and the separation of the genetic variants of K-casein were accomplished by altering the electrophoretic conditions. Manson (1965) fractionated acid casein on a starch gel column stabilized by a density gradient at 25 °C. 

In this context, some experimental results relevant to these open questions of enzymatic degradation will be presented and will be discussed from the viewpoint of cellulose chemistry, together with a summary of our recent work on thermohydrolysis and acid hydrolysis of cellulose, performed in connection with research on cellulose powder manufacture (7). After a short survey of the experimental techniques applied, this contribution will be centered on three problems (1) the interaction of chain degradation and cross-linking in thermal and thermo-hydrolytic treatments of cellulose, (2) the influence of mechanical strain... 

Larvae of IL electellum were raised on artificial wheat germ-based diets to which varying concentrations of 8 6 SC had been added. This compound was dissolved in acetone, coated on cellulose powder under vacuum and then mixed into the diet at concentrations of 0.01%, 0.1% and 1%. The control diet contained cellulose powder which had been soaked in acetone and dried under vacuum. At levels of 0.1% and 1%, 8 6 SC significantly reduced pupal weight (Table 5). However, larval survival and development time were not affected. 

SC was dissolved in acetone and coated on cellulose powder which was added to the diet to give the concentrations indicated. Control diet contained cellulose powder which had been soaked in acetone. Each concentration was tested on at least 100 larvae. 

Tylophora crebriflora S. T. Blake (T. floribunda Benth.) occurs in North Queensland. Extraction of the plant material with hot methanol afforded the crude mixture of alkaloids which was purified by chromatography on cellulose powder using propanol-2 N acetic acid as the eluent. Further purification by repeated chromatography yielded tylophorine (Bf 0.5 in butan-l-ol-acetic acid 97 3) and tylocrebrine (R 0.2 in the same solvent system) (mp 218°-220° [a] D — 45° + 2° (c 0.1, CHCI3). (+ )-Tylocrebrine isolated from Ficus septica Forst. f. was found (4) to have mp 220°-222° and [a] f + 20.5° + 2° (c 0.8, CHCI3). 

Stachydrine from Medicago saliva (L.) Grimm was found to be contaminated with homostachydrine, C8H15O2N, which was isolated as the hydrochloride (mp 216°-217° decomp. [a]jj —13.3° in ethanol) by chromatography of crude stachydrine hydrochloride on cellulose powder (189). The structure CXXXIII was proven by methylation of the silver... 

Alternatively, Pd(OAc)2/TPPTS was immobilized on cellulose powder [25]. The new support was also tested in allylic substitution using 3 and 4 as starting materials (cf. Scheme 4). Cellulose-supported complexes were also dependent in their activity on the degree of hydration. Here, two maxima were observed. This was explained by the swelling properties of cellulose in water the surface area increases by two orders of magnitude, thereby enhancing the surface accessibility and activity [26]. With 26 wt% water, the first maximum was reached. The second one was obtained when the amount of water was raised to 66 wt%. The increase of surface accessibility mentioned above was observed. Complete conversion occurred within 100 min with 66 wt%. With 26 wt%, only 60% conversion was obtained for the same reaction time. 

Folates [pteroylmonoglutamates (PteGlu)] and related compounds were separated by TLC on cellulose powder (MN300 UV254) with 3.0% (wt/vol) NH4CI and 0.5%... 

Schneider and Hoestetter [68] have separated various food colorants in pill coatings used in pharmaceutical preparations, on cellulose powder layers. 

Esseb [210] describes a quantitative determination of the ninhydrin-positive compounds separated on cellulose powder MN 300. 

Three extracellular cellulases have been purified from the cultures of a Cellulomonas species. One was found in solution in the cell-free supernatant and two others were found to be bound to the cellulose added as a carbon source. The free enzyme and one of the cellulose-bound enzymes exhibited binding for Sephadex . The two cellulose-bound enzymes are glycoproteins. All three enzymes behaved as ewffo-cellulases towards soluble carboxymethylcellulose and had little activity on cellulose powder. 

Using the solvent system propanol-pyridine-acetic acid-water (15 10 3 12) on cellulose powder, TLC plates gave excellent separations of the water-soluble antibiotics according to Ito et al. A ninhydrin reagent or an oxidized nitroprusside reagent was used as the identification system. Based on and color, 20 basic antibiotics were separated. For six closely related compounds, in terms of Rp, the solvent system consisting of water-saturated butanol plus 2% p-toluenesulfonic acid was successful in differentiation. 

In 1937, Mayer, Mark, and Misch conducted the X-ray experiment on cellulose powder, which resulted in determining a unit cell of cellulose 1 that is still regarded as an early reference. On the basis of X-ray diffraction pattern, researchers proposed a model with monoclinic unit cell (a = 8.35 A b = 7.0 A c = 10.3 A y = 96°) with chains oriented antiparallety [7]. One unit cell was situated in the corner, while the other at the center of the cell, parallel with the chain axis (Fig. 21.3). In this approach, the alternating glucose units of the chain were rotated through 180° so that the origin... 

Fig. 2. Elution curve of a column electrophoresis on cellulose powder of the phenolase preparation shown in Fig. la. Total protein 240 mg., 0.01 M Na2HP04, 800 volts, 25 mA., 10 hours. The abscissae show milliliters of eluate. The ordinates show absorbancy at 280 m i (dashed line), at 340 mu (dotted line), and enzymic units (solid line). From Kertesz and Zito (1962b).

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