دورية أكاديمية
GALT deficiency causes UDP-hexose deficit in human galactosemic cells.
| العنوان: | GALT deficiency causes UDP-hexose deficit in human galactosemic cells. |
|---|---|
| المؤلفون: | Lai K; Department of Pediatrics, Emory University School of Medicine, 2040 Ridgewood Drive, Atlanta, GA 30322, USA. klai@med.miami.edu, Langley SD, Khwaja FW, Schmitt EW, Elsas LJ |
| المصدر: | Glycobiology [Glycobiology] 2003 Apr; Vol. 13 (4), pp. 285-94. Date of Electronic Publication: 2003 Jan 03. |
| نوع المنشور: | Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S. |
| اللغة: | English |
| بيانات الدورية: | Publisher: IRL Press at Oxford University Press Country of Publication: England NLM ID: 9104124 Publication Model: Print-Electronic Cited Medium: Print ISSN: 0959-6658 (Print) Linking ISSN: 09596658 NLM ISO Abbreviation: Glycobiology Subsets: MEDLINE |
| أسماء مطبوعة: | Original Publication: Oxford ; New York : IRL Press at Oxford University Press, c1990- |
| مواضيع طبية MeSH: | Fibroblasts/*metabolism , Galactosephosphates/*metabolism , UTP-Hexose-1-Phosphate Uridylyltransferase/*deficiency , Uridine Diphosphate Glucose/*deficiency, Cell Line, Transformed ; Cell Transformation, Viral ; Cells, Cultured ; Fibroblasts/drug effects ; Fibroblasts/virology ; Galactose/pharmacology ; Galactosephosphates/pharmacology ; Glycosylation ; Humans ; Kinetics ; Phenotype ; Simian virus 40/genetics ; Transfection ; UTP-Glucose-1-Phosphate Uridylyltransferase/genetics ; UTP-Glucose-1-Phosphate Uridylyltransferase/metabolism ; UTP-Hexose-1-Phosphate Uridylyltransferase/genetics ; UTP-Hexose-1-Phosphate Uridylyltransferase/metabolism |
| مستخلص: | Previously we reported that stable transfection of human UDP-glucose pyrophosphorylase (hUGP2) rescued galactose-1-phosphate uridyltransferase (GALT)-deficient yeast from "galactose toxicity." Here we test in human cell lines the hypothesis that galactose toxicity was caused by excess accumulation of galactose-1-phosphate (Gal-1-P), inhibition of hUGP2, and UDP-hexose deficiency. We found that SV40-transformed fibroblasts derived from a galactosemic patient accumulated Gal-1-P from 1.2+/-0.4 to 5.2+/-0.5 mM and stopped growing when transferred from 0.1% glucose to 0.1% galactose. Control fibroblasts accumulated little Gal-1-P and continued to grow. The GALT-deficient cells had 157+/-10 micromoles UDP-glucose/100 g protein and 25+/-5 micromoles UDP-galactose/100 g protein when grown in 0.1% glucose. The control cells had 236+/-25 micromoles UDP- glucose/100 g protein and 82+/-10 micromoles UDP-galactose/100 g protein when grown in identical medium. When we transfected the GALT-deficient cells with either the hUGP2 or GALT gene, their UDP-glucose content increased to 305+/-28 micromoles/100 g protein (hUGP2-transfected) and 210+/-13 micromoles/100 g protein (GALT-transfected), respectively. Similarly, UDP-galactose content increased to 75+/-12 micromoles/100 g protein (hUGP2-transfected) and 55+/-9 micromoles/100 g protein (GALT-transfected), respectively. Though the GALT-transfected cells grew in 0.1% galactose with little accumulation of Gal-1-P (0.2+/-0.02 mM), the hUGP2-transfected cells grew but accumulated some Gal-1-P (3.1+/-0.4 mM). We found that 2.5 mM Gal-1-P increased the apparent KM of purified hUGP2 for glucose-1-phosphate from 19.7 microM to 169 microM, without changes in apparent Vmax. The Ki of the reaction was 0.47 mM. Gal-1-P also inhibited UDP-N-acetylglucosamine pyrophosphorylase, which catalyzes the formation of UDP-N-acetylglucosamine. We conclude that intracellular concentrations of Gal-1-P found in classic galactosemia inhibit UDP-hexose pyrophosphorylases and reduce the intracellular concentrations of UDP-hexoses. Reduced Sambucus nigra agglutinin binding to glycoproteins isolated from cells with increased Gal-1-P is consistent with the resultant inhibition of glycoprotein glycosylation. |
| معلومات مُعتمدة: | M01-RR00039 United States RR NCRR NIH HHS |
| المشرفين على المادة: | 0 (Galactosephosphates) 2255-14-3 (galactose-1-phosphate) EC 2.7.7.10 (UTP-Hexose-1-Phosphate Uridylyltransferase) EC 2.7.7.9 (UTP-Glucose-1-Phosphate Uridylyltransferase) V50K1D7P4Y (Uridine Diphosphate Glucose) X2RN3Q8DNE (Galactose) |
| تواريخ الأحداث: | Date Created: 20030311 Date Completed: 20040112 Latest Revision: 20131121 |
| رمز التحديث: | 20231215 |
| DOI: | 10.1093/glycob/cwg033 |
| PMID: | 12626383 |
| قاعدة البيانات: | MEDLINE |
Full Text Finder | تدمد: | 0959-6658 |
|---|---|
| DOI: | 10.1093/glycob/cwg033 |