UNIDENTIFIED VITAMINS 



TABLE XI 



8i 



Properties of Certain Liver Fractions Containing Antipernicious Anemia 



Factor 



ciates yielded arginine, glycine, leucine, aspartic acid, hydroxyproline, 

 and proline on hydrolysis. 



Now that the chemistry of pteroylglutamic acid and its related con- 

 jugates is known, it is likely that more rapid progress will be made in 

 the isolation of the liver antipernicious anemia factor (s). The unknown 

 factor or factors for pernicious anemia in liver and other sources are 

 possibly the outstanding unidentified factors of today, if importance 

 is judged by the amount of clinical evidence on therapeutic usefulness. 



Just as pteroylglutamic acid has antipernicious anemia activity, 

 pteroyltriglutamic acid has been reported recently by Spies to have 

 activity also. It is effective (Table XII), but pteroylheptaglutamic acid 

 (vitamin Be conjugate) has been found by Welch and his associates 

 to be ineffective in pernicious anemia in relapse. A possible relationship 

 between the utilization of pteroylglutamic acid and the extrinsic factor 

 is a subject for interesting speculation and study. 



About a year ago Cline, Berry, and Spies announced the isolation of 

 a new leukopoietic factor from a liver extract which was active in 

 leukopenia. 



