title: Specific tritium labeling of glucosyl- and galactosylceramides at the 6-position of the carbohydrate moiety using CrO3-graphite.
abstract: A new procedure for introducing tritium into the carbohydrate portions of glucosyl- and galactosylceramides was developed using a new catalyst, CrO3-graphite, which specifically oxidizes the primary alcohol group to the aldehyde. About 10% of the glycolipid was converted to the aldehyde and the aldehyde produced was then reduced back to the original form with KB3H4. After methanolysis, more than 96.7% of the radioactivities of [3H]glucosyl- and [3H]galactosylceramides were found to be located in the carbohydrate portions, and the specific activities of the [3H]galactosyl- and [3H]glucosylceramides were 2.08 to 4.30 X 10(4) cpm/nmol, which could be increased greatly by purifying the aldehydes and reducing them with KB3H4. In addition, beta-galactosidase activity was successfully determined with [3H]galactosylceramide as the enzyme substrate; the Km was 18.73 mM and the Vmax was 11.63 nmol/mg/h, indicating that no significant structural modification occurs during the oxidation.
authors.forename: S
authors.initials: S
authors.lastname: Usuki
authors.forename: Y
authors.initials: Y
authors.lastname: Nagai
mesh_terms: D000818:Animals; D001894:Borohydrides; D002241:Carbohydrates / Q000032:analysis; D002384:Catalysis; D002417:Cattle; D002554:Cerebrosides / Q000032:analysis*; D055598:Chemical Phenomena; D002621:Chemistry; D002857:Chromium; D017608:Chromium Compounds; D005692:Galactose Oxidase; D005699:Galactosylceramides / Q000032:analysis*; D005963:Glucosylceramides / Q000032:analysis*; D006108:Graphite; D006801:Humans; D007553:Isotope Labeling; D010084:Oxidation-Reduction; D014316:Tritium; D001616:beta-Galactosidase
chemical_list: D001894:Borohydrides; D002241:Carbohydrates; D002554:Cerebrosides; D017608:Chromium Compounds; D005699:Galactosylceramides; D005963:Glucosylceramides; D002857:Chromium; C028371:potassium borohydride; D014316:Tritium; D006108:Graphite; D005692:Galactose Oxidase; D001616:beta-Galactosidase; C023600:chromic oxide