title: Elevation of 4 beta-galactosyltransferase activity for paragloboside synthesis in sera of patients with cancer.
abstract: Galactosyltransferase activities in sera of cancer patients were determined by assaying the formation of paragloboside from UDP-galactose and lactotriaosylceramide immobilized on microtiter plates by means of the enzyme-linked immunosorbent assay using a monoclonal antibody, H-11, directed to paragloboside. Enzyme properties were as follows. Optimum pH was 6.8 in cacodylate buffer, and Km values were 2 microM for lactotriaosylceramide and 29 microM for UDP-galactose. The enzyme activity was inhibited by the addition of alpha-lactalbumin. Glucose (20 mM) inhibited the enzyme activity in the presence of alpha-lactalbumin (0.1 mg/ml) but not in its absence. These enzyme properties are similar to those of bovine milk galactosyltransferase, indicating that the enzyme in the sera might be lactose synthetase. The enzyme activities in sera from patients with cancer, patients with benign disease, or a reference sample group were assayed. The activity was below the limit of detection (5.5 pmol/25 microliters serum/2 h) in the reference sample group. Remarkable elevations of the enzyme activity were observed with high incidence in patients with cancer, especially those with blood cancer (100%). A high incidence was observed in the progressive stage, and the enzyme activity was detected at stage 1 in lung, esophagus, stomach, colorectal, and testis cancer. The enzyme activity in sera from patients with benign disease was elevated in 22% of the patients. After effective therapies, the enzyme activity decreased to below the limit of detection. Release of the galactosyltransferase into culture medium of cancer cells could be demonstrated. These observations suggest that the galactosyltransferase is released from cancer tissue into the circulation. The present method for the assay of galactosyltransferase may be useful for the detection of patients with cancer and for monitoring neoplastic recurrence after therapy.
authors.affiliation: Department of Biochemistry, Tokyo Medical and Dental University, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Nishiwaki
authors.forename: T
authors.initials: T
authors.lastname: Taki
authors.forename: N
authors.initials: N
authors.lastname: Handa
authors.forename: N
authors.initials: N
authors.lastname: Hattori
authors.forename: K
authors.initials: K
authors.lastname: Takeshita
authors.forename: M
authors.initials: M
authors.lastname: Endo
authors.forename: S
authors.initials: S
authors.lastname: Handa
mesh_terms: D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor / Q000097:blood; D002240:Carbohydrate Sequence; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005700:Galactosyltransferases / Q000097:blood*; D005915:Globosides / Q000096:biosynthesis*; D006028:Glycosphingolipids / Q000096:biosynthesis / Q000276:immunology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007768:Lactalbumin / Q000494:pharmacology; D007938:Leukemia / Q000097:blood / Q000201:enzymology; D008223:Lymphoma / Q000097:blood / Q000201:enzymology; D008297:Male; D008969:Molecular Sequence Data; D009369:Neoplasms / Q000097:blood / Q000201:enzymology*
chemical_list: D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; D005915:Globosides; D006028:Glycosphingolipids; C036363:paragloboside; D007768:Lactalbumin; D005700:Galactosyltransferases