Effect of organic cosolvents on the stability and activity of the β-1,4-galactosyltransferase from bovine colostrum

• Published in: Carbohydrate research 1997-12, Vol.305 (3), p.525-531
• Main Authors: Riva, Sergio, Sennino, Barbara, Zambianchi, Francesca, Danieli, Bruno, Panza, Luigi
• Format: Article
• Language: English
• Subjects: Animals; Cattle; Colchicine - analogs & derivatives; Colchicine - metabolism; Colchicoside; Colostrum - enzymology; Coumarins - metabolism; cow colostrum; Enzyme Stability - drug effects; Fraxin; galactosyltransferase; Galactosyltransferases - metabolism; Glycosides - chemical synthesis; Glycosylation; Lactalbumin - metabolism; Magnetic Resonance Spectroscopy; Molecular Structure; Organic cosolvents; Solubility; solvents; Solvents - pharmacology; UDP-galactose-4′-epimerase; UDPglucose 4-Epimerase - metabolism; Uridine Diphosphate Galactose - metabolism; β-1,4-Galactosyltransferase
• ISSN: 0008-6215; 1873-426X
• DOI: 10.1016/S0008-6215(97)00273-5

The influence of various organic cosolvents on the stability and activity of the β-1,4-galactosyltransferase from bovine colostrum (GalT) and of its ancillary enzyme UDP-galactose-4′-epimerase has been investigated using the glucosylated alkaloid colchicoside ( 1) as a model substrate. It has been found that some cosolvents, such as Me 2SO and MeOH, can be used up to 20% v/v without any influence on the performance of these enzymes, while others, such as tetrahydrofuran, rapidly inactivated GalT at concentrations as low as 5% v/v. These results have been exploited for the galactosylation of the poorly water soluble coumarinic glucoside fraxin ( 2). Graphic