a dialyzed serum medium was used to investigate the nutritional qualities of various compounds when tested as substitutes for the ultrafiltrate fraction . l-asparagine was the only amino acid that markedly stimulated growth . l-glutamine was active only when autoclaved ( converted to the ammonium salt of pyrrolidone carboxylic acid ) , and nh ( 4 ) cl and urea satisfactorily replaced l-asparagine .
C0002520
amino
C0017797
glutamine