Open AccessReversal of UDP-galactose 4-epimerase deficiency of human leukocytes in culture.
Author(s) -
Brent Mitchell,
E. Haigis,
B Steinmann,
R Gitzelmann
Publication year - 1975
Publication title -
proceedings of the national academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.72.12.5026
Subject(s) - derepression , enzyme , lymphoblast , nad+ kinase , galactose , microbiology and biotechnology , biochemistry , biology , galactokinase , enzyme assay , locus (genetics) , cell culture , chemistry , genetics , escherichia coli , gene , psychological repression , gene expression
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.
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