Peptones Witte

H. SchsStteb. Ueber die Albumosen des Pepton Witte, Zeils. f. physiol. Chem., 1898, (26), p. 338. 

Syntonm. (Abderhafdea and Sasaki Hart.) Hetero-albumoset from Syntonin. (Hart.) Prot-albumose, from Syntonm. (Hart.) DeuterO clbnmose. from Witte 8 Peptone. (Haslam.) Hetero-albumose. from Witte s Peptone. (Haslam.) Protein in Urine. (Abder-halden and Prcgl.)... 

Yeast requires for its growth certain salts which are present in Witte s peptone. If the latter is not available it may be replaced by 20 cc. of a solution made by dissolving 10 grams each of potassium phosphate, magnesium chloride, and calcium nitrate in 1 liter of water. 

Further examples from the work of Sorensen have been collected below. Column a refers to an invertase solution containing 6 c.c. of citrate and 4 c.c. of alkali as. buffer mixture. Column h refers to a somewhat acidified 2% glue solution. Column c concerns a 2% Witte peptone solution, slightly acidified with hydrochloric acid. Column d deals with a 2% egg white solution. It is evident that in every case here recorded, the pH s determined colorimetrically exceed those measured electro-metrically. 

Barnett Cohen found the following values in 5% Witte peptone. 

If Witte peptone dissolved in ten times its weight of salt water (0.7%) is injected into the jugular vein of a dog in the proportion of 0.3 g. per kg. of animal, it is found that five to ten minutes after the introduction of the solution, the blood which is collected is no longer spontaneously coagulable. This can then be centrifuged and a peptonized plasma obtained. 

The five fractions separated in Witte peptone are likewise found in the products of hydrolysis, either with adds, or with enzymes of all protein substances The limits of pre-dpitation of the four albumoses, according to their different origins, are given in the following table ... 

In a solution of 20 per cent Witte peptone, the limits of first fraction are. 

The small extent of our knowledge as to the nature of al-bumoses, and even as to the differentiation of the various natural albuminoids, readers it difficult to quote a single experiment solving the question The problem is almost solved, however, with data assembled from different sources It was Levene and van Slyke who first determined quantitatively, according to the method established by E Fischer, the amino-acids given by hydrolysis with 20 per cent HCl of a plastein and of Witte peptone from which it was derived. 

In the table above, as Witte peptone comes from a transformation of fibrin, we have given the composition of the products obtained after hydrolysis of the latter with acid. These ana lytical data show beyond doubt that plastein is a very complex substance, approaching closely the albiuninoids in composition. Moreover, of all the products which are found in peptone, only the fraction precipitable by phosphotungstic acid can give rise to a plastein of composition analogous to that given above. 

These results confirm the fact that plastein possesses a greater molecular complexity Ilian Witte peptone but that it does not exceed that of hetero-albumose, much less that-of fibrin. Sawja-loff, to show the synthetic nature of plasteins, calculates by... 

Witte peptone hydrolyzed with pepsin + HsSOi 37 0 13 6 37 9 13 2... 

Witte peptone moderately hydrolyzed. Witte peptone strongly hydrolyzcil... 

It therefore results from all this data that plasteins arc of a very complex protein nature, which approache.s in certain points that of natural albuminoids, but which differs from it, however, from the point of view of formaldehyde nitrogen. The special nature of plasteins and their differentiation from the natural albumins appears also from the work of Herrmann and Chain. By inoculation of rabbits with plastein coming from Witte peptone, consequently from fibrin, they obtained an anti-serum which... 

Secretin pre-exists in the intestine it is not, as was believed for some time, found in the state of pro-secretin, which a treatment with HCl would have the effect of transforming into active substance. The best proof of this fact is that secretin can be isolated without the use of add, by treating the duodenal mucous membrane with boiling salt solutions, with lo per cent solutions of Witte peptone, with bile salts, with urea, and even by pressure. 

J. Baker and Hulton, in 1908, found in wheat flour a proteolytic enzyme capable of transforming the nitrogenous materials of the grain into various hydrolytic products, among which is tryptophane. This enzyme, which acts similarly on Witte s peptone, was identified with erepsin by these writers. 

It appears from this table that Witte s peptone, the product of peptic hydrolysis of fibrin, contains still a very large quantity... 

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