Hexone bases

Foster, G. L and C. L. A. Schmidt The Separation of the Hexone Bases from Certain Protein Hydrolysates by Electrolysis. J. biol. Chem. 56, 545 (1923). 

These last substances, lysin and arginin, together with histidin previously cited, form the three hexonic bases, thus named because of their six atoms of C. They are met in the decomp>osition of most albuminoid materials, and play an important rdle in their constitution. They are all three precipitable by phosphotungs-tic add. Various salts, by giving with them metallic derivatives more or less soluble, offer a means of separation. 

The complete analysis of the products of tryptic digestion would involve, in addition to the separation and the determination of albumoses and remaining peptones, the characterization of the hexonic bases formed, as well as the qualitative and quantitative examination of the various amino-adds appearing. Unfortunately, in the present state of the sdence, no general method exists which permits, by a systematic course, the attainment of this end. At most, we can merely note the methods of Drechsel, Kutscher, and Kossel for analyzing hexonic bases, and... 

Arginase, already described, decomp>oscs Jirginin, giving urea and omithin. Now, arginin, a hexonic base, Ls a sui)stanee which is found in the products of the hydrolysis of the major part of albuminoid material. It is thus concdvabic that by this method of division a certain quantity of protein nitrogen can escape the transformation to urea. 

In addition to these various products, more or less characteristic of putrefaction, there are still others which come from the action of amidases on the diamines resulting from the thorough decomposition of the albuminoid molecule. Thus it is that arginin, the hexonic base which we encounter in most of the products of proteolysis, is transformed first by the action of arginase into urea and into omithin ... 

In the same way 1), which is another hexonic base, is transformed into cadaverin and CO2 ... 

I. Aromatic Acids, Dicarboxylic Acid and Hexonic Bases, Biochim. biophys. Acta 3, 82-91 (1949). 

In the next year (Foster and Schmidt, 1923), the investigation was extended to other proteins casein, fibrin, and red blood cells. Instead of adding sulfuric acid to the cathode compartment, carbon dioxide w as bubbled through it. The middle compartment was cooled by running water and stirred. The completeness of the separation depended upon the time employed, but, for preparative purposes, it was not found worth while to wait for more than 90 % of the hexone bases to be transported to the cathode. After a second run, this solution contained 98.5 to 100% basic nitrogen. 

Aldonamides are readily prepared by reaction of lactones with liquid ammonia (86,99,100), with ammonium hydroxide (101,102), or by bubbling ammonia gas into alcoholic solutions of the sugar lactones (103-104). Aldonamides of the tetronic adds are stable in aqueous solution (105), but penton- or hexon-amides are hydrolyzed, as shown by the change of the optical rotation of the amide solutions (106). The hydrolysis is catalyzed by acids and bases, and the product was the ammonium salt of the aldonic acid. 

Starting from D-galactono-1,4-lactone, 2-keto-3-deoxy-D-hexonic acids with either the D-erythro (119) or D-threo configuration (120) were obtained in only three steps.318 Epimerization at C-4 occurred during the base-catalyzed /1-elimination reaction on the galactonolactone derivative 136. 

E. Vigne, I. Mahfouz, J. F. Dedieu, A. Brie, M. Perricaudet, and P. Yeh, RGD inclusion in the hexon monomer provides adenovirus type 5-based vectors with a fiber knob-independent pathway for infection, J. Virol. 73 5156 (1999). 

An unusual classification of hexonic acids described by Levene21 was based on the differences in optical rotation between the free acid and its sodium salt. For example, in the D-gluconic acid series the sodium salt has the more positive rotation whereas in the D-mannonic acid group the reverse is the case and the acid has the more positive rotation. In comparison with these results glucosaminic acid was found to have a rotation of —15° (and its sodium salt +1.3°) and therefore these derivatives were in conformity with the D-gluconic acid series. 

Liquid extraction methods are based on the differential distribution coefficients of Zr and Hf between aqueous and organic phases. For example, hexone and other ketones (such... 

The adenovirus capsid is an icosahedral capsid that can be described as pseudo-T=25. The 12 pentameric vertices are each composed of 5 molecules of the penton bases, carrying a trimeric fiber. The 20 faces are composed of the 4 molecules of hexon protein, which itself is a trimer of the 967-residue-long polypeptide II. The crystal structure of the hexon has been solved and it reveals that the trimeric subunits are intimately intertwined, thus accounting for their observed stability. The capsid also... 

F3. Flagg, J. F. Solvent Extraction Processes Based on Hexone, in Chemical Processing of Aqueous Fuels, J. F. Flagg (ed.). Academic, New York, 1961, chap. 6. 

A step further in the utilization of these solvent-extracted compounds is their use as reagents. Irving and co-workers (8, 16) have reported what they call a colored liquid anion exchanger based on this concept. They use a xylene-hexone solution of tetrahexylammonium erdmannate. Erdmannate ion is the yellow [Co(NH3)2(N02)4] anion, which absorbs strongly at 353 m/x in aqueous solution. The exchange reaction is... 

Two principal solvent-extraction methods are used for the production of high-grade zirconium, based upon the solvents hexone (methyl-isobutyl-ketone) and tributyl phosphate. In both cases, the aim is to purify the zirconium from its chemical homologue, hafnium, but in some variants of the process the other metallic impurities are also removed. It is also possible to obtain the hafnium in a pure condition if required, and to obtain fairly good yields of both zirconium and hafnium. 

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