Reversal of UDP-galactose 4-epimerase deficiency of human leukocytes in culture.

Mitchell B, Haigis E, Steinmann B, Gitzelmann R. "Reversal of UDP-galactose 4-epimerase deficiency of human leukocytes in culture." Proc. Natl. Acad. Sci. U.S.A.. 1975;72(12):5026-30.


Stimulation with phytohemagglutinin of the leukocytes from six of the seven known individuals with UDP-galactose 4-epimerase (= UDP-glucose 4-epimerase; EC deficiency consistently resulted in the appearance of epimerase activity in the cultured cells. A long-term lymphoblast culture derived from one proband also contained an active epimerase enzyme. A comparison of the properties of this enzyme with those of epimerase produced by control lymphoblast lines revealed comparable Km values for UDP-galactose and NAD and identical behavior on polyacrylamide electrophoresis. However, a difference in the NAD requirement for heat stability at 40 degree provided some evidence for a structural defect in this enzyme. Possible explanations for the appearance of UDP-galactose 4-epimerase activity in stimulated lymphocytes include an increased rate of synthesis of a mutant enzyme and a derepression of an epimerase locus during lymphocyte transformation.



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