IV. PIOCIII'.MK \1 



^^ siiiM.- 



ASS 



COOH 

 I 

 CHNH: 



I 



CH. 

 I 

 COOH 



Asportato 



COOH 



Funuinite 



COOH 

 I 

 CH, 



CHOH 

 I 

 COOH 



COOH 



I 

 CH2 



I 

 CHo 



I 

 COOH 



Malatc 



Succinate 



III lliis fully rcxiTsihlc dcaininat ion 110 keto analog is produced; ncitiu'i' 

 oxalacetate nor its decomposition product, pyruxate. 



The deamination of alanine, i)henylalanine, methionine, or glutamic 

 acid was not stimulated by hiotin under experimental conditions under 

 which l)i()tin was found to be effecti\'e in promoting the deamination of 

 aspartic acid. 



In aging cells the deaminase acli\ity may l)e restored not only by biotin 

 hut also by muscle adenylic acid (adenosine-o-phosphoric acid). Fiu'ther- 

 more it has been found that both biotin and adenylic acid stimulate the 

 foi'mation of aspai'tic acid from ammonia and malate, pi'obably owing to 

 a dii'ect action on the deaminase rather than to a remo\al of oxalacetate 

 from tile reaction system. ^^ The stimulation l)y biotin is almost immediate 

 whereas that l)y adenylic acid usually recjuires a lag period. \\'ith prolonged 

 incul)ation the stimulation by adenylic acid may exceed that produced 

 by biotin. "This was taken as an indication that adenylic acid may be 

 ser\-ing as a non-specific energy soui-ce supplying the energy necessary to 

 synthesize the actixc coenzyme foiin of biotin, or that it is specifically 

 necessary t(^ phospiiorylate i)iotin.""'' 



In some experiments the r(nicti\ation of '"aging cells" was achie\'ed l)y 

 biotin only at pll 7.0 but not at pll 4."^ In other instances it was found'" 

 that during aging the cells may l)ecome moi'e dependent on adenylic acid 

 and will not respond to biotin. With the change in the composition of the 

 media, "aging" may produce biotin deficiency or adenylic acid deficiency.^* 



F]ven in cell-free juice pi'e])ai-ed fiom K. coli, dialyzed against phosphate 



'•"■ M. C. I,iclit.s1(>iti :in(l J. F. Cliristmaii, ./. Biol. Chciti. 175, 649 (1948). 



"■ I,. I). Wrifilit. K. I., ("rcsson and H. H. Skoggs, Proc. Soc. Expll. Biol. Med. 72, 



.556 (1949). 

 ■ A. K. Axolrod. I\. Hotniann, S. V.. I'urvis. and .M. .Mayliall, ./. Biol. ('hem. 175, 



991 (1948). 

 «H. C. Lichtstpin. ./. Biol. Chnn. Ill, IS7 (1949). 

 "S. J. Ajl, \V. \\. Halt, ..n<l C. H. W.Tkn.an, Euzyinologia 14, 1 (1950). 



