( 376 ) 



citrate (see Behrens). Citraconic acid must tiierefore be present in 

 tiie sublimate and after adding NH,, evaporating and redissoiving in 

 water, crystals of the thallous salt of citraconic acid were actually 

 obtained on adding thallous nitrate. 



Once I obtained crystals of silver malate, after the addition of 

 AgNOj, it might therefore be possible, that, malic acid was here 

 formed as well as citric acid. 



Both acids are known to be final or intermediate products in the 

 decomposition of sugar, I have already mentioned malic acid ^) in 

 this connexion, and Wehmer-) has shown that Citroniyces spec, 

 Penicillium luteum and Mucor pyriformis, when grown in sugar 

 solutions produce citric acid; this acid also frequently occurs in 

 Phanerogams (comp. Czapek. Biochemie der Pflanzen). 



Whether in addition to citric and perhaps malic acid, other less 

 known acids are also formed by the enzyme in the decomposition 

 of glucose is of course still an open question. 



If we calculate the quantities of acid found as citric acid 

 [C3H,OH(COOH)3-fH,0, mol. weight 210] we find: 



I experim. for 77 mg. glucose 34 mg. COj and 63 mg. citric acid 



)i 5> x ( D ,, ,, 



5> 5> Id. 5 ,, ,, 



It is mj' intention by using more material to determine the quantity 

 of citric acid foi'med, for only then can it be ascertained whether 

 the decomposition of sugar to CO3 and citric acid is complete. It 

 seems natural at the same time to investigate what enzymes are 

 present in the crude enzyme, whether oxygen is absorbed in the 

 process and how the object beha\es after freezing by Palladin's 

 method, questions which the method explained above leaves un- 

 answered. 



The results of this investigation can be summarised as follows. 



By pressing out and precipitating the press juice with alcohol or 

 acetone, there can be obtained from the spadix of Sauromatum 

 venosum Schott. a crude enzyme, that decomposes glucose with the 



1) A preleminary experimeat was carried out in order to obtain from the leaves 

 of Echeveria spec, in the same way as here from Sauromatum a crude enzyme 

 that produced GO2 and malic acid from glucose, but with negative result. 



The malic acid of Crassulaceae, which has been investigated by J. H. Aberson 

 (Ber. chem. Ges. 1898) yields in sublimation little or no fumaric and maleic acid, 

 but gives an amorphous silver salt. 



2) G. Wehmer. Ber. d.d. bot. Ges. 1893. 



