524 ENZYMES DECOMPOSING SACCHARIDES. 



is generally used as a precipitant for enzymes. Moreover, it 

 cannot be separated from invertase, and therefore, according to 

 Emmerling, the best raw material for maltase is Schizosaccharo- 

 tnyces octosporus, which does not contain invertase. 



The optimum temperature for this enzyme is given by LINTNER 

 and KROBER (I.) as 40 0., whereas that of GEDULD'S glucase (II.) 

 varies between 57 and 60 C. This difference indicates that the 

 various enzymes decomposing maltose are not identical ; and it is 

 therefore advisable to speak of the yeast enzyme as yeast- maltase, 

 and not simply maltase. 



The destruction temperature was determined by LINTNER and 

 KHOBER (I.) as 55 0., which was also confirmed by BAU (XXVI.). 

 Dry maltase has greater power of resisting high temperatures ; 

 for, though BOKORNY (IV.) found that the maltase in a pressed yeast 

 was destroyed in the dryiDg process, E. FISCHER (VII.), as well as 

 LINTNER and KROBER (I.), had previously ascertained that the 

 enzyme would stand careful drying. According to BAU (XXVI.), 

 the enzyme remains unimpaired when top- or bottom-fermenta- 

 tion yeast is dried at the ordinary temperature, or at 35-37 0., 

 the dried yeast being then heated for several hours at 105 C. 

 (though in this case the maltase is slightly weakened), or stored 

 for over five years. Bau regards maltase, however, as far more 

 sensitive than invertase to desiccation; so that there is no 

 considerable discrepancy between his statements and those of 

 Bokorny. 



The influence of chemical reagents was investigated more 

 particularly by BOKORNY (IV.) in the same manner as for invertase 

 (see p. 520, vol ii.), the results showing maltase in pressed yeast 

 to be more sensitive than that in brewery yeast. The enzyme 

 remained unaffected by the action of 0.5 per cent, solutions of 

 lactic acid and oxalic acid, caustic soda, o.i per cent, sulphuric 

 acid and phenol, and by chloroform water (on this point see later). 

 It was more or less enfeebled by 0.5 per cent, sulphuric acid, 

 i per cent, acetic acid, o.i per cent, formaldehyde and thymol, 

 o.ooi per cent, oil of turpentine, and 5 per cent, alcohol ; whilst 

 the following agents had a destructive effect : o.i per cent, 

 hydrochloric acid, i per cent, oxalic acid, caustic soda, or phenol, 

 0.02 per cent, sublimate, o.oi per cent, silver nitrate, and loper 

 cent, alcohol. By subjecting bottom-fermentation yeast UF to 

 similar treatment, BAU (XXVI.) observed a destructive effect on 

 the maltase by i per cent, acetic acid, 0.5 and i per cent, oxalic 

 acid, i per cent, lactic acid, 4 per cent, tartaric acid, 0.5 and 

 i per cent, sulphuric acid, 0.91 per cent, hydrochloric acid, i per 

 cent, caustic soda, o. i-o.oi per cent, silver nitrate, and o. i per cent, 

 sublimate. The enzyme was also injured by 0.2 per cent, oxalic 

 acid, i per cent, sodium carbonate, 0.5 per cent, caustic soda, 

 0.02 per cent, sublimate, and 95 per cent, (vol.) alcohol. With 

 reference to Bokorny's report (above) that maltase is uninjured 



