144 K. BAHADUR 



Isoleucine 



The formation of threonine has been described before. It can act as the starting 

 material for formation of isoleucine as described below. 



CH3CH(OH)CH(NH2)COOH + CH2O -.-- CHOCH(CH3)CH(NH2)COOH (51) 



2H + CHOCH(CHü)CH(NH2)COOH ^ OHCH2CH(CH3)CH(NH2)COOH (52) 



CH2O + OHCH2CH(CH3)CH(NH2)COOH ^ 

 CHOCH2CH(CHa)CH(NH2)COOH + H2O (53) 



CHOCH2CH(CH3)CH(NH2)COOH + 2H ?i 



OHCH2CH2CH(CH:,)CH(NH2)COOH (54) 



OHCH2CH2CH(CH3)CH(NH2)COOH + CH2O ^ 



CHO • CH2 • CH2 • CH(CH3)CH(NH2)COOH + H2O (55) 



CHOCH2CH2CH(CH3)CH(NH2)COOH + O ^ 



COOHCH2CH2CH(CH3)CH(NH2)COOH (56) 



COOHCH2CH2CH(CH3)CH(NH2)COOH ^^ 

 CH3CH2CH(CH3)CH(NH2)COOH + CO2 (57) 



(Isoleucine) 



Valine 



Alanine can be synthesized as described above. This can act as starting 

 material for the synthesis of valine, 



CH3OH H\ 



+ >CHCH(NH2)COOH ^^ (CH3)2CHCH(NH2)COOH + 2H2O (58) 

 CH3OH H/ VaUne 



It should be noted that in the formation of all these amino acids, the reactions 

 considered can easily take place under laboratory conditions with the help of 

 light and are generally taking place in plants in the biogenesis of plant products. 



The interconversion of the amino acids described is similar to that observed 

 in the various biological tissues. In the formation of glycine and serine, 

 NH = CHCOOH is the chief initial product which on hydrogénation becomes 

 glycine (7) and on condensation with a formaldehyde molecule becomes serine 

 (8). A close relationship is observed between glycine and serine in biological 

 tissues also where glycine can be utilized in the formation of serine in the 

 presence of vitamin B12 [12-15]. 



Proline, ornithine and glutamic acid are synthesized from CHO • CH2CH2- 

 CH(NH2)C00H (13), (14), (15), (17), (31), (32). Shemin & Rittenberg [16] 

 also found proUne and ornithine to be interconvertible and it is probable that 

 their interconversion involves a-aminoglutaraldehydic acid. Glutamic acid and 

 proUne have also been found to be interconvertible in liver and kidney tissues 



[17-19]. 



Aspartic acid can easily give alanine by decarboxylation (39). Kritsman [20- 

 22], Wood & Werkman [23], Evans & Slotin [24] and Braunshteïn [25] observed 

 the interconversion of aspartic acid and alanine through oxaloacetic and pyruvic 

 acid stages. According to them, aspartic acid, formed by the amination of 

 oxaloacetic acid, transaminatcs with pyruvic acid to form alanine and oxaloacetic 

 acid. It is, however, quite possible that in a photochemically activated mixture, 

 as is considered here, these amino acids arc related by decarboxylation and 

 carboxylation reactions. 



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