Specific maltose labeling in the reducing glucose moiety

✍ Scribed by Chon R. Shoaf; Michael Caplow; William D. Heizer

• Book ID: 102984356
• Publisher: Elsevier Science
• Year: 1979
• Tongue: English
• Weight: 670 KB
• Volume: 96
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(79)90547-5

✦ Synopsis

Radioactive maltose with label in the reducing glucose moiety was prepared using a giucosyltransferase enzyme to catalyze exchange of [6-3H]glucose into unlabeled maltose. The enzyme was isolated from spinach by ammonium sulfate precipitation followed by DEAE column chromatography. A 77% yield of [6-3HJmaltose was obtained after a reaction of 100 nmol of maltose with 0.0147 nmol of [G+H]gIucose was catalyzed by the most active column peak. The product was exclusively Iabefed in the reducing glucose moiety as indicated by the label occurring only in sorbitol following sodium borohydride reduction and sulfuric acid hydrolysis. Between 88.3 and %.O% of the tritium in the synthesized preparation was present as [6-3H]maltose by Dowex l-X4 chromatography. This column separates [6-3H]maltose-[U-1*C]maItose mixtures and [6JH]glucose-[U-W]glucose mixtures apparently as a result of an isotope effect.