Galactose metabolism in transferase-deficient galactosaemic and normal long-term lymphoid cell lines.
The activity (mean +/- SD) of galactose-1-phosphate uridyl transferase in two long-term lymphoid cell lines from Caucasian patients with transferase deficiency galactosaemia, a heterozygote, and eight normal subjects was 0, 78 and 168 +/- 55 nmol UDPG consumed (mg protein)-1h-1, respectively. Also, no activity was found in erythrocytes and cultured fibroblasts from the patients. A small number of cells of the galactosaemic lines cultured in medium, in which galactose was substituted for glucose, survived for 37 days. Normal and galactosaemic lines incubated with D-galactose-[1-14C] liberated 218.2 +/- 65.6 and 18.1 pmol 14CO2 (mg cellular protein)-1 (6h)-1, respectively. The evolution of 14CO2 from D-glucose-[1-14C] was similar in normal and galactosaemic lines. In the presence of [3H]galactose the radioactivity incorporated into TCA-precipitated material of the galactosaemic lines was 6.8% of the normal lines. Approximately 26% and 1.3% of the total radioactivity was incorporated into molecular species with a molecular weight greater than 400,000 daltons in normal and galactosaemic cells, respectively. Similar molecules were identified in the cell-free medium of both normal and deficient cells except for an 18,000 daltons molecule identified only in the medium of the normal cells. These findings indicate that a small amount of galactose is metabolized in galactosaemic lines with no transferase activity.
Beratis
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Department of Human Genetics, New York State Institute for Basic Research in Developmental Disabilities, Staten Island 10314.
Wilbur
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L
D002245:Carbon Dioxide / Q000097:blood; D002460:Cell Line; D002850:Chromatography, Gel; D005347:Fibroblasts / Q000378:metabolism; D005693:Galactosemias / Q000175:diagnosis*; D006579:Heterozygote; D006801:Humans; D008214:Lymphocytes / Q000201:enzymology / Q000378:metabolism*; D009713:Nucleotidyltransferases / Q000172:deficiency*; D013936:Thymidine; D005694:UTP-Hexose-1-Phosphate Uridylyltransferase / Q000097:blood / Q000172:deficiency*
D002245:Carbon Dioxide; D009713:Nucleotidyltransferases; D005694:UTP-Hexose-1-Phosphate Uridylyltransferase; D013936:Thymidine