Reversal of UDP-galactose 4-epimerase deficiency of human leukocytes in culture.
Stimulation with phytohemagglutinin of the leukocytes from six of the seven known individuals with UDP-galactose 4-epimerase (= UDP-glucose 4-epimerase; EC 5.1.3.2) 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.
D002238:Carbohydrate Epimerases / Q000172:deficiency*; D002239:Carbohydrate Metabolism, Inborn Errors / Q000201:enzymology*; D002478:Cells, Cultured; D004355:Drug Stability; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D037102:Lectins / Q000494:pharmacology; D007962:Leukocytes / Q000201:enzymology*; D008214:Lymphocytes / Q000201:enzymology; D014534:UDPglucose 4-Epimerase / Q000097:blood / Q000172:deficiency*
D037102:Lectins; D002238:Carbohydrate Epimerases; D014534:UDPglucose 4-Epimerase