Galactose metabolism in transferase‐deficient galactosaemic and normal long‐term lymphoid cell lines

Abstract

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.

Uridine Diphosphate Hexoses in Leukocytes and Fibroblasts of Classic Galactosemics and Patients with Other Metabolic Diseases

“…However, the examination of leukocyte galactose metabolism in galactosemics may give a more accurate assessment of the defect than can be obtained in erythrocytes. Long-term lymphoid cell lines have been used in galactosemic studies (19). In this regard, our own findings that leukocyte sugar nucleotide content is not different in granulocytes or lymphocytes (9) suggest that immortalized lymphocytes may be a suitable model for study of UDPhexose metabolism.…”

Culture of galactosaemic fibroblasts in the presence of galactose: Effect of inosine

“…Although this time of culture before the death of galactosaemic cells was too short to study the real effect of galactose, we could distinguish galactosaemic cells from normal cells. This medium was used to segregate normal cells from galactosaemic cells (Benn et al, 1981;Beratis and Wilbur, 1987). However, when the galactosaemic cells were cultured in standard medium up to the stationary phase and then in galactose medium instead of glucose medium, they did not die and their microscopic aspects were not altered.…”