| Literature DB >> 1748 |
B Mitchell, E Haigis, B Steinmann, R Gitzelmann.
Abstract
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.Entities:
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Year: 1975 PMID： 1748 PMCID： PMC388868 DOI： 10.1073/pnas.72.12.5026
Source DB: PubMed Journal: Proc Natl Acad Sci U S A ISSN： 0027-8424 Impact factor: 11.205