Observations on the Presence of Pteroyl Polyglutamates in Human Serum

Treatment of serum with folic acid conjugase obtained from fresh chicken pancreas indicated the presence therein of polyglutamyl derivatives of pteroic acid. The polyglutamyl derivatives appeared to belong to a group higher than the triglutamate.

Two groups of subjects, one with normal level and the other with low level of unconjugated folate, were studied. In the normal group, the level of unconjugated serum folate varied between 3.2 and 18.0 ng./ml., while that of total folate (unconjugated plus conjugated) varied between 14.0 and 47.0 ng./ml. In the other group, the level of unconjugated folate varied from 2.0 to 2.6 ng./ ml., while that of total folate varied from 14.5 to 31.0 ng./ml. No significant difference, either in the individual values or in their means, was noticed in the two groups of subjects.