ANTI-ENZYMES 59 



increases during digestion (Rosenthal^^) ; it is increased during preg- 

 nancy"'* and the blood of the fetus shows less than that of the mother. 

 Normal antitrypsin unites with trypsin according to the law of mul- 

 tiple proportions (Meyer) and the reaction is not reversible (Ronfloni). 

 It is found in the urine, and in infianunatory exudates, but not in 

 normal serous fluids, and it resists putrefaction. Normal serum does 

 not seem to inhibit the enzymes which act upon purines. Fuld and 

 Spiro"* found that the natural antirennin of normal horse serum is in 

 the pseudoglobulin fraction. Since acids destroy the anti-enzyme 

 property of the serum, it is not effective against pepsin-HCl mixtures. 

 Against trypsin, however, it is very effective. Zunz^*^ states that nor- 

 mal serum acts more upon enterokinase than upon trypsin, and believes 

 that the inhibition depends upon colloids which modify surface ten- 

 sion and adhere to the proteins. Red corpuscles and living unicellular 

 organisms, including bacteria, are likewise resistant to trypsin, and 

 normal serum also seems to contain an antirennin. ^^ 



Oppenheimer and Aron^* consider it probable that the re- 

 sistance of normal serum to trypsin digestion depends upon the con- 

 figuration of the protein molecules, which perhaps, when in fresh, 

 uninjured condition, present no suitable surfaces for attack by the 

 ferment. Hedin attributes antitrj^ptic action to adsorption of the 

 enzyme by some constituent of the serum, much as charcoal inhibits 

 tryptic digestion. 



Fresh and inactivated serum will prevent pepsin from digesting 

 protein, but this is not due to a true antipepsin, according to Ham- 

 burger."^ 



Jobling^" and his co-workers have advanced evidence that the nor- 

 mal antiprotoase action of serum depends on the lipoids of the senuii,^^ 

 which var}^ in activity directly with the degree of unsaturation; there- 

 fore they were able to decrease the antiferment action of serum by 

 extracting the lipoids with fat solvents (and to restore the activity 

 by replacing the lipoids), or by saturating the double bonds of the 

 fatty acids with halogens, or by modifying the degree of dispersion 



8' Folia Serologica, 1910 (6), 285; also Franz and Jarisch, Wien. klin. Woch., 

 1912 (25), 1441. 



" See Franz, Arch. f. Gyn., 1914 (102), 579. 



«5Zeit. f. physiol. Chem., 1900 (31), 132. 



*8 Mem. Acad. roy. med. Belgique, 1909 (20), fasc. 5. 



" Czapek (Ber. Deut. botan. Gesell., 1903 (21), 229) states that anti-oxidases 

 occur normally in certain plants, strongly specific against the oxidase of the same 

 plant species. 



°8 Hofmeister's Beitrage, 1903, (4), 279. 



«3 Jour. Exper. Med., 1911 (14). 535; Arch. Int. Med., 1915 (16), 356. There 

 seems to be no relation between the antipeptic and antitrvptic powers of sera 

 (Rubinstein, Ann. Inst. Pasteur., 1913 (27), 1074). 



I 1 '" Series of articles in Jour. Exper. Aled. ; also review in Jour. Lab. and Clin. 

 Med., 1915 (1), 172. See also Zeit. Immunitat., 1914 (23), 71. 



" Yamakawa (Jour. Exp. Med., 1918 (27), 689), liowever, does not believe 

 that the antienzyme which prevents autolysis of serum itself is of lipoidal nature. 



