The Problem of the Origin of the Proteins 



287 



substance and all is extracted for 10-20 min. It is centrifuged and filtered. In 

 the extract are also phosphatase and pyrophosphatase. 



PREPARATION OF THE REACTION MIXTURES 

 For each experiment 4 tests are performed. I : Extract 2 ml + phosphate 

 0-0375 M (pH 8-4) (0-5 ml) + 0-04 M arsenite (0-2 ml) + vitamin Bi (200 /xg). 

 II: the same as the first, but vitamin Bi is omitted (control). Ill: extract (2 ml) 

 + phosphate (0-5 ml) + arsenite (0-2 ml) -f vitamin Bi (200 jug) + i-o m dl- 

 alanine (o-i ml). IV: the same as the third, but vitamin Bi is omitted. The total 

 quantity of the mixtures is 3-2 ml; presence of oxygen. After 2 hours of incubation 

 all the tests are boiled for 2-3 min. (immediately before boiling, the vitamin Bi 

 is added), cooled, diluted and refrigerated. 



PREPARATION OF SAMPLES FOR ASSAY 

 Ethiozymase (0.2 g) diluted in phosphate (pH 6-2) (i ml) + phosphate (pH 

 6-2) (i ml) + 0-2 ml of a solution containing MgCl2 (i mg) and MnCl2 (100 /xg) 

 + 2-5 ml of centrifuged fluid are put in a Warburg flask; in the side arm is put 

 sodium pyruvate (0-5 ml, 10 mg). 



The synthesis of the cocarboxylase is expressed in mm^ of extra CO2, obtained 

 from the difference between the CO2 of the test incubated with vitamin Bi and 

 the test without Bi (control — test). The two experiments reported in Table i 

 are examples of many other experiments which always gave the same results. 



Table i 



Acellular System which is able to synthesize Cocarboxylase from 

 Vitamin Bi and inorganic Phosphate 



A similar model must be used, from my point of view, in the tentative 

 reproduction of virus on artificial medium. 

 Working experimentally in both these two directions, I think and hope that 



