ENZYMES 



57 



attack cell-walls. Negative results are only of value as preliminary tests, for the 

 action may be dependent upon special circumstances, or upon special combinations 

 of circumstances. According to Griiss those diastases which dissolve certain reserve- 

 celluloses do not appear to act upon ordinary cellulose, whereas Brown and Morris 

 state that the diastase from barley-malt attacks ordinary cellulose but leaves reserve- 

 cellulose intact '. 



According to de Bary (Bot. Zeitung, 1886, pp. 419, 422) the enzyme of Peziza 

 sclerotiorum which rapidly dissolves cell-walls exercises no action upon starch-paste. 

 [Newcombe 2 has shown that a cellulose-enzyme is present in seedlings of barley, 

 lupins, and dates, as well as in Aspergillus oryzae. If extracts of equal diastatic 

 value are prepared, those from Lupinus and Phoenix dissolve cellulose in about 

 nine hours or so, those from Aspergillus and barley-malt in about 100 hours. 

 Newcombe concludes that distinct amylohydrolytic and cellulose-dissolving cyto- 

 hydrolytic or cytase ferments are present, but the facts also coincide with the 

 supposition that a single specific ferment is present in each extract, and that 

 the different varieties of diastase possess varying powers of dissolving starch and 

 cellulose.] 



Invertin and glucoside-ferments . Several varieties of invertins or invertases 

 exist, all characterized by the power of splitting soluble di- and poly-saccharides : 

 thus Saccharomyces cerevisiae produces a readily diosmosing invertin which splits 

 cane-sugar into dextrose and laevulose, and also a ferment which can only with 

 difficulty be extracted, and which decomposes maltose 3 . Both of these leave milk- 

 sugar intact, whereas the lactase of Saccharomyces Kefir decomposes both lactose 

 and saccharose 4 . On the other hand, emulsin decomposes lactose but not cane- 

 sugar and maltose 5 , while inulin is decomposed by the inulase of Compositae, but 

 not by the invertin of beer-yeast 6 . Fernbach has even shown that the typical 

 saccharose-invertins of different plants exhibit certain specific peculiarities, and 

 future comparative studies will probably reveal many other forms of invertin. 

 Their action upon polysaccharides is not their only one, for the glucase which 

 splits maltose, as well as the emulsin which decomposes amygdalin, are invertins. 

 Glucosides and the ether-like compounds of carbohydrates with other substances, 

 show in many respects a resemblance to the group of poly-saccharides, and hence 



1 Griiss, Jahrb. f. wiss. Bot., 1894, Bd. xxvr, p. 408; Bibliotheca hot., 1896, Heft 39, p. 13. 

 In a reserve-cellulose composed of different hemicelluloses, the latter may dissolve in succession. 

 Brown u. Morris, Bot. Zeitung, 1892, p. 464; Reinitzer, Zeitschr. f. physiol. Chemie, 1897, Bd. XXIII, 

 p. 208. 



2 [Newcombe, Bot. Centralbl., Bd. LXXIII, 1898, No. 4; Annals of Botany, 1889, Vol. xm, 

 p. 49.] 



3 E. Fischer, Ber. d. Chem. Ges., 1895, p. 1433. On the distribution of invertins, cf. Fliigge, 

 Mikroorganismen, 1896, 3. Aufl., p. 202. 



4 Beyerinck, Centralbl. f. Bact., 1890, Bd. vi, p. 44; E. Fischer, Ber. d. Chem. Ges., 1894, 

 pp. 2991, 3481. 



5 E. Fischer, 1. c., 1894, p. 2990; 1895, p. 1431. 



6 Green, Annals of Botany, 1888, Vol. I, p. 223; 1893, Vol. vn, p. 89. E. Fischer (1. c., 1894, 

 p. 2988) states that invertin is inactive upon inulin. Bourquelot has shown that certain fungi are 

 able to split inulin (Compt. rend., 1893, T. cvi, p. 1143). Cf. Sect. 82. Fernbach, Ann. d. 1'Inst. 

 Pasteur, 1890, T. iv, p. 641. 



