Cultured cells of human
transitional cell carcinoma line MGH-U1, in
suspension, were assayed for galactosyl
transferase by measurement of the transfer of [3H]
galactose from
uridine diphosphate:[3H]
galactose to
desialylated ovine submaxillary mucin. The assay was optimized with respect to time and to
protein,
uridine disphosphate:
galactose, desialyated ovine submaxillary
mucin, and
Triton X-100 concentrations. This assay was then applied to fresh specimens of benign, inflamed, and neoplastic bladder epithelium from 33 patients who under went cold-cup biopsies at cytoscopy.
Transitional cell carcinoma specimens gave values in the range of 24.7 to 184.8 cpm [3H]
galactose transferred per microgram
protein per hr [72.0 +/- 44.7 (S.D.); n = 25]; normal and inflamed specimens ranged from 0.8 to 46.1 cpm/microgram
protein per hr [8.3 +/- 8.4 (S.D.); n = 35]. By using a known method of cell
rupture, cell ghosts, representing cell-surface membranes, were isolated both from the cultured cell line and from two biopsy specimens of
transitional cell carcinoma. Although a complete enzymatic and electron microscopic analysis was not undertaken, the coincidence of an
enzyme marker with the cell ghost fraction containing the elevated galactosyl
transferase made it appear probable that this
enzyme is located in the cell surface.