DE956045C - Process for the production of high-sulfur conversion products from proteins - Google Patents

Description

Process for the production of high-sulfur conversion products from protein substances In patent 943 227 a process for the production of thiolactams is described, that consists in the fact that lactams with thiocarboxylic acids of the type of thioacetic acids, expediently at elevated temperatures. The carboxamide group becomes -N H-C O- the lactams converted into the thiocarboxamide group -N H-C S-.

When transferring this working method to linear polyamides of the kind of polycaprolactam one receives sulfur-containing products, which the sulfur also mainly contained in thiocarboxamide bond. It has now been found that one can also convert protein substances into higher-sulfur conversion products, if you combine them with low molecular weight saturated aliphatic thiocarboxylic acids from the type of thioacetic acid C Hs-C O S H treated. This too will be obvious Carboxamide groups converted into thiocarboxamide groups.

It is noteworthy that in the reaction with such thiocarboxylic acids Approximately the same amounts of sulfur are incorporated into the protein molecule as into linear ones Polyamides, namely about 2 to 3.5%. That supports the assumption that it is included at least predominantly about a similar process, namely the replacement of carboxamide against thiocarboxamide groups.

Attempts have been made several times to check the sulfur content of proteins to increase under mild conditions. So far, however, they have always been terminal free amino groups thioacylated.

E. Loiseleur (Comptes Rendus des Seances de-1'Academie des Sciences, Vol. 2o1, 1935, p. 967) treated casein with carbon disulfide in order to introduce dithiocarbamic acid ester groups into the protein molecule (cf. equation I). R. Micheel (Angewandte Chemie [A], Vol. 60, 1948, p. 69) then transferred that described by AR Todd (Journal of the Chemical Society [London, 1936, p. 155; 1946, p. 647; Annual Report of the Progress of Chemistry, Vol. 41, 1944, p. 200) conversion of primary amines with dithioformic acid to proteins and was able to determine an increase in sulfur corresponding to the lysine content of the protein bodies (see formula scheme II). A. S ehöber 1 (Angewandte Chemie [A], Vol. 60, 1948, p. 7) followed a similar path when he reacted dithioglycolide with casein and was also able to determine a sulfur uptake that was dependent on the lysine content (see formula scheme III) . A. Schöber 1 achieved an increase in the sulfur content from 0.8io / o to 2.18o / o. M. Bakes (Comptes Rendus des Seances, Vol. 225, 1947, p. 533) finally tried to use the phosphorus pentasulfide method according to AW H offmann on peptides, without success.

The method according to the invention differs from these known ones Process insofar as here not new sulfur-containing groups to the free primary Amino groups of the lysine residues of the protein molecule are bound, but that the Uptake of sulfur on the conversion of carboxamide to thiocarboxamide groups is based. It is known that thiocarboxylic acids of the type of thioacetic acid only have acylating effects on primary amino groups, with hydrogen sulfide escapes. This acylating effect occurs with the treatment of proteins Thioacetic acid undoubtedly also includes. But if, as was found, at the same time Sulfur is built into the protein molecule, so the incorporation of the sulfur must be here be done in a different way than in the known processes described above, d. H. not by the reaction with the free amino groups. From the above The fact that thiocarboxylic acids are of the thioacetic acid type in the case of lactams and the polyamides convert carboxamide groups into thiocarboxamide groups, one can conclude that the sulfurization of the proteins found by thiocarboxylic acids of the type of thioacetic acid also on the conversion of carboxamide based in thiocarboxamide groups. This effect of the thiocarboxylic acids was for the protein chemistry new and surprising.

However, it has also been found that when exposed to thiocarboxylic acids from the type of thioacetic acid to proteins, expediently at ordinary temperature, possibly after dissolution of the substance, also depending on the duration of the action a partial degradation to low molecular weight, dialyzable fractions and to such of higher molecular weight which are not dialyzable; he follows. For example In this way, a high molecular weight crystalline product can be made from gelatine significantly increased sulfur content can be obtained in the starting material. .

It is therefore possible that this degradation is due to a reaction of the thiocarboxylic acid with certain groupings, e.g. B. thiazoline or oxazoline rings, which are used as building blocks be accepted by proteins (M. Bergmann, Naturwissenschaften, Vol. 12, 1924, P. 1158; K. L i n d e r s t r ö m-Lang and G. F. Jacobsen, Comptes Rendus des Laboratoires Carlsberg, Vol. 23, 1941, p. 289; S. Blackburn and H. Phillips, Biochemical Journal, Vol. 38, 1944, p. 171) or thioimino ether compounds (G. C. E h r e n s v ä r d and B. Davidson, Arkiv för Kemi, Mineralogi och Geologie, Vol. 24, 19q.6 / 1947, S. i) takes place. As was stated in another context, namely react certain thiazoline derivatives and also other nitrogen-containing heterocyclic compounds easily with thiocarboxylic acids of the thioacetic acid type.

The non-enzymatic breakdown of protein bodies has hitherto been carried out almost exclusively hydrolytically with the aid of aqueous mineral acids or alkalis. A. Fodor et al. (Enzymologia, Vol. 1, 1936, p. 311; Vol. 4, 1937, p. 36; Vol. 5, 1938, p. 6o; Vol. 6, 1938, p. 1o8; Vol .6, 1938/1939, p. 122, 194, t04 2 0 7; Vol. 8, 194o, p. 219, 311) described a process for the degradation of proteins by heating to 14o ° in anhydrous solvents such as glycerol, ß -Naphthol or glacial acetic acid. The products formed in this way (“acripeptides”) should each be made up of four amino acid residues or a multiple thereof, although the possibility of secondary formation of these from peptides cannot be ruled out. In contrast, the process according to the invention is a reaction in which, even if degradation occurs, products that are richer in sulfur are obtained.

The according to the present process z. B. Crystalline, sulfur-rich products obtainable from gelatin have no antigenic properties. They can therefore be administered parenterally to the warm-blooded animal. In addition to their pharmacological usability, the products obtainable by the present process are also important for the production of plastics and as textile auxiliaries. EXAMPLE 100 g of commercially available, bleached edible gelatine are refluxed with 50 cc of thioacetic acid on a boiling water bath for 4 hours, the evolution of hydrogen sulfide being observed.

After cooling, the reaction mixture is filtered off from a little undissolved material and the filtrate was precipitated with zoo cc of ether. The remaining viscous mass is with Ether triturated and then in an extraction device with ether for so long pulled out until the colorless running-off solvent with sodium nitroprusside no There is more sulfur reaction. After drying in a vacuum desiccator over caustic alkali 7 g of a yellowish, odorless and tasteless powder are obtained, the sulfur content of which cannot be detected with sodium nitroprusside and it decomposes at 120 °.

2 g of this preparation are dissolved in water and 3 days against distilled Dialyzed water. The solution remaining in the dialysis tube is placed in a vacuum desiccator evaporated over sulfuric acid. One receives i, 1 g of a sulfur-containing, brown Resin, which is ground to a brown powder with ether; Melting point below Gas development at 95 °, blackening with foaming at 165 °.

Analysis of Starting Material (Edible Gelatin) Found N: 14.930 / 0; 14.840 / 0; S found: 0.96%; Ash found: 1.340 / 0; Water content found: 15.68%.

Analysis of Sulfurized Product: Found N: 14.380 / 0; S found: 3.48%; Ashes: traces. An approximately equal increase in the sulfur content of gelatine is achieved if thiopropionic or thiobutyric acid is used instead of thioacetic acid. Example 2 8 g of edible gelatine of the same consistency as in Example i are poured with 50 cc of thioacetic acid and left to stand for 14 days at ordinary temperature with occasional shaking, everything gradually dissolving without any swelling being observed.

After the reaction has ended, the reaction mixture is filtered and the The filtrate was precipitated with ether. After the exhaustive extraction with ether as in the example After drying, 6.5 g of an odorless and tasteless, pale yellow one remain behind Powder that decomposes at 180 °.

The product is suspended in water by shaking in solution brought and then dialyzed against distilled water for 4 days. The content of the The dialysis tube is filtered and evaporated over sulfuric acid in a vacuum desiccator. 2.4 g (equal to 4o0 / 0) of the reaction product used are specific light, pale yellowish, fibrous, crystalline, odorless and tasteless, sulfur-containing, obtained water-soluble substance.

This crystallized preparation decomposes at 23o ° without melting.

Analysis: Found N: 14.900 / 0; S found: 2.05%; Ashes: traces. example 30 cc of thioacetic acid are poured over 3 i o g casein (according to H a m m a r s t e n) and refluxed on the boiling water bath for 36 hours. With moderate evolution of hydrogen sulfide the reaction mixture swells strongly and takes on a reddish yellow color. To When standing at night, the gelatinous reaction product is squeezed out on the suction filter, rubbed in the mortar with ether to a yellow-colored powder and then- exhausted with ether.

It is then suspended in 50 cc of distilled water and 4 Dialyzed for days. The powdery residue remaining after drying from the Dialysis sleeve represents a colorless, odorless and tasteless, sulfur-containing Powder. Yield 4.6 g.

Analysis of starting material: Found N: 13.96%; i3,880 / 0; S found: o.99%; Ashes found: i, i6%.

Analysis of the Sulfurized Product: Found N: 12.85%; S found: 3.61; Ash: 0.450 / 0. Example 4 iog casein (according to Hammars te n) are doused with 50 cc of thioacetic acid and left to stand for 3 weeks with occasional shaking. The casein begins to swell with a slight evolution of hydrogen sulfide. The swelling subsides after about 14 days; then the reaction mixture is worked up. The excess thioacetic acid is sucked off sharply and the residue is treated with ether in an extraction device, as described in Example i. Then the product is dialyzed for 4 days. After drying, the residue from the dialysis sleeve is a colorless, sulfur-containing, odorless and tasteless powder that decomposes at 242 ° with slurry. Yield 4.8g.

Analysis of the sulfur-containing product: Found N: 14.420 / 0; S found: 3.60%; Ash: 0.72 %.

Claims (1)

PATENT CLAIM: Process for the production of high-sulfur reaction products from protein substances, in which the sulfur is converted into the carboxamide. groups is introduced, characterized in that protein substances, expediently at room temperature, are treated with low molecular weight saturated aliphatic thiocarboxylic acids of the thioacetic acid type. Considered publications: Angewandte Chemie (A), Vol. 6o, 1948, p. 69.