RECENT WORK IN AGRICULTURAL SCIENCE. 



ACtRICTJLTTJRAL CHEJOSTRY— ACtEOTECHNY. 



Biochemical catalysts in life and industry. — Proteoljrtic enzyms, J. Er- 

 FEONT (Xew York: John Wiley d Sons, Inc., 1011, pp. XI-\-151). — This is a 

 translation, by S. C. Prescott, assisted by C. S. Venable, of the French test 

 previously noted (E. S. R., 32, p. 662). 



The effect of potassium bromate upon enzym action, I. S. Faxk; and C. E. 

 A. WiNSLOw {Jour. Biol. Cliem., S3 (1918), No. 3, pp. 4.53-462) .—The action of 

 potassium bromate upon trypsin and pancreatin was investigated by means of 

 digestion experiments with casein and determination of the amino acids pro- 

 duced in the presence of varying amounts of the salt. From the experimental 

 data the authors conclude that " potassium bromate appears to exert consist- 

 ently favorable influence upon the digestion of casein by trypsin in vitro in the 

 dilutions studied, the action being most marked at bromate concentrations of 

 1 : 100,000 to 1 : 200,000. Potassium bromate in concentrations of one part or 

 more in 10,000 appears to exert a slight inhibitive influence upon the digestion 

 of casein by pancreatin, while in higher dilutions (1:200,000 or 1:250,000) it 

 appears to exert a stimulating action." 



It would thus appear that in the strength in which it is used in Arkady Yeast 

 Food (1:200,000) potassium bromate may exert a specific stimulating action 

 upon the proteolytic enzyms active in the fermentation. 



Some new constituents of milk. — III, A new protein, soluble in alcohol, 

 T. B. Osborne and A. J. Wakeman (Jour. Biol. Chem., 33 (1918), No. 2, pp. 

 243-251). — The authors, in cooperation with G. S. Leavenworth and O. L. 

 Nolan, give in detail the method of preparation and physical and chemical 

 properties of the alcohol soluble protein of milk previously noted (E. S. R., 38, 

 p. 505). The protein was obtained by concentrating the alcoholic washings 

 from a large quantity of casein which had been several times dissolved in 

 dilute alkali and precipitated by dilute hydrochloric acid. It was soluble in 

 50 to 70 per cent alcohol but insoluble in absolute alcohol and nearly so in 

 water containing more or less inorganic salts. 



The average composition of this protein obtained by a series of fractional 

 precipitations was, on the ash- and moisture-free basis, as follows : Carbon 54.91 

 per cent, hydrogen 7.17, nitrogen 15.71, sulphur 0.95, phosphorus 0.08, and 

 oxygen (by difference) 21.18. The distribution of nitrogen, according to Haus- 

 mann's modified method, was amid nitrogen 1.56 per cent, basic nitrogen 2.55, 

 and humin nitrogen 0.21. The basic amino acids calculated by the Kossel 

 method were, per 100 gm. of milk protein, arginin 2.92 gm., histidin 2.28, lysin 

 3.98, and tyrosin 2.47. 



Compared with casein the alcohol-soluble protein contains more carbon and 

 sulphur and less phosphorus, basic nitrogen, arginin, histidin, and lysin. It does 

 not resemble the alcohol-soluble proteins of vegetable origin in being character- 

 ized by a large proportion of amid nitrogen and less lysin than most proteins. 

 Further evidence that it is not related to casein was shown by negative 

 anaphylaxis reactions with casein although it is itself highly anaphylactogenic. 



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