38y 



Much strongei is tlie defending influence of 1,06 milligram- 

 molecule glutamic acid and of 1,06 milligiammolecule tyrosine, 

 which compensate the action of about 2 cm' 1,06 normal NaOH- 

 solution (polarisation after 37, hours). 



Glutamic acid acts just like tj^rosine as almost two basic acid, 

 which was once more confirmed foi- the latter compound by the 

 experiment described in table lUb. 



It must be remarked that the glutamic acid (N°. 7) did not quite 

 dissolve even after being shaken repeatedly. 



Nevertheless ± 14 cm' of the clear solution were used at the 

 beginning for the determinion of polarisation. 



In the remaining alkalic liquid all the glutamic acid was dissolved 

 after some time (within 'S^/^ hours). The tyrosine (N". 8, table Ilia 

 and N°. 3, table lUb) was dissolved but little. At the addition of 

 the NaOH-solution after being shaken it was quite dissolved. ^) 



The addition of hydrochloric acid too causes the rapid solution 

 of tyrosine. 



This compound in this regard resembles substances such as zinc- 

 hydroxide and aluminiumhydroxide. 



In acidic solution the glutamic acid dissolved but gradually. I 

 did not determine polarisation before all had dissolved. Although 

 the glutamic acid therefore could not be active to a certain extent 

 at the beginning of tlie experiments, from the results obtained it can 

 be concluded with rather great certainty that glutamic acid in 

 acidic solution behaves as monacidic alkali. 



Tyrosine too (table IV, N". 6) behaves in acidic solution as 

 monacidic alkali ; J milligrammolecule compensates the action of 

 about 1 cm^ of normal hydrochloric acid. 



Asparagine acts as ■V4-acidic alkali ; 2 milligrammolecules com- 

 pensate the invertive action of about 1,5 cm' of normal hydrochloric 

 acid (Table IV, N". 5). 



Afterwards aniline and pyridine were subjected to research, in 

 how far these compounds influence the destruction of glucose by 

 alkali and the inversion of sucrose by hydrochloric acid. 



C,H,.NH, Aniline. 



Molecular weight = 93 

 C^H.N. Pyridine. 



Molecular weight = 79 



1) In heating the solution to the boiling point but without the addition of NaOH 

 the tyrosine dissolved almost quite, but in cooling till the ordinary temperature 

 was reached an important quantity crystalhsed, which was dissolved rapidly at 

 the addition of NaOH. 



