DEGRADATION OF PROTEIDS, ETC. 371 



precipitant. The action of the enzyme is retarded by an acid 

 reaction, neutrality being the most favourable condition and 

 alkalinity highly prejudicial. Casein and uncoagulated albumen 

 are also attacked, though less powerfully, whilst coagulated 

 albumen and egg albumen are left intact. Milk casein, thrown 

 down by the lab enzyme, is gradually dissolved. Though nothing 

 certain is yet known about the final product of the reaction, this 

 protease is apparently different from pepsin, pancreatin and 

 papayin. BUTKEWITSCH (I.) also occupied himself with the enzy- 

 matic proteolysis effected by the same fungus. According to 

 DUCLAUX (VII.), " Penicillium glaucum" contains tryptic casease 

 in addition to the lab enzyme (see vol. i. p. 243). The further 

 degradation of protein by the fungi under consideration results 

 finally in the formation of amino acids and ammonia. Aspergillus 

 niger, however, as was shown by WEHMER (V.) in 1892, forms 

 large quantities of ammonium oxalate in solutions of peptone, 

 5 grms. of peptone furnishing more than 2 grms. of calcium 

 oxalate; and, according to KOSJATSCHENKO (I.), it also produces 

 from the protein of peas, tyrosiri, leucin, histidin, arginin and 

 lysin. On the other hand, according to BUTKEWITSCH (L), " Peni- 

 cillium glaucum " seems to furnish chiefly amino acids (leucin and 

 tyrosin), so that tryptic enzymes are apparently in question, as 

 was proved by SAITO (II.) by the formation of tryptophane in the 

 case of nineteen species of fungi. Some practical importance 

 also attaches to the question of the degradation of protein in the 

 ripening of certain cheeses (Brie, Camembert and Roquefort) by 

 species of Penicillium, on which point reference should be made 

 to the labours of Roger, Epstein, Jensen and Thorn. 



The coagulation of milk is effected in 2-10 days by all the 

 species examined on this point by SCHAEFFER (IV.), viz., Asp. 

 niger, A.fumigatus, A. glaucus, A. Wentii, A. oryzw (2 days in 

 this case), Penic. glaucum (in 3 days), P. luteum, P. italicum, and 

 P. rubrum. These species also peptonised milk casein, coagulated 

 egg albumen, fibrin (except Penic. glaucum and P. rubrum), and 

 vegetable casein. TEICHERT (I.) also pointed out that "Peni- 

 cillium glaucum " has a decided degrading action on casein, and, 

 according to CONN, THOM, BOSWORTII, STOCKING and ISSAJEFF (I.), 

 both the technical Penicillium species of Roquefort and Camem- 

 bert cheese (P. Roquefort and P. Camembert) also attack cheese by 

 an excreted proteolytic enzyme. Lab enzyme was also found by 

 SAITO (II.) in Asp. oryzce. Similarly, according to Swanoff, Asp. 

 niger and " Penic. glaucum " contain an enzyme (nuclease) which 

 splits up the nucleo-proteids into xanthin bases and phosphoric 

 acid. 



SHIBATA (I.) states that Asp. niger produces an enzyme, or 

 group of enzymes (amidases), furnishing ammonia, like urase. 

 The triturated, dead mycelium acts on urea , biuret and certain 

 acid amides (acetamide, oxamide), with formation of ammonia. 



