Maillard reactions and increased enzyme inactivation during oligosaccharide synthesis by a hyperthermophilic glycosidase.
The thermostable Pyrococcus furiosus beta-glycosidase was used for oligosaccharide production from lactose in a kinetically controlled reaction. Our experiments showed that higher temperatures are beneficial for the absolute as well as relative oligosaccharide yield. However, at reaction temperatures of 80 degrees C and higher, the inactivation rate of the enzyme in the presence of sugars was increased by a factor of 2 compared to the inactivation rate in the absence of sugars. This increased enzyme inactivation was caused by the occurrence of Maillard reactions between the sugar and the enzyme. The browning of our reaction mixture due to Maillard reactions was modeled by a cascade of a zeroth- and first-order reaction and related to enzyme inactivation. From these results we conclude that modification of only a small number of amino groups already gives complete inactivation of the enzyme.
Bruins
M E
ME
Department of Food Technology and Nutritional Sciences, Food and Bioprocess Engineering Group, Wageningen University, P.O. Box 8129, 6700 EV, Wageningen, The Netherlands. Marieke.Bruins@Algemeen.pk.wau.nl
Van Hellemond
E W
EW
Janssen
A E M
AE
Boom
R M
RM
D004789:Enzyme Activation; D004795:Enzyme Stability; D006027:Glycosides / Q000138:chemical synthesis; D006358:Hot Temperature; D007700:Kinetics; D007785:Lactose / Q000737:chemistry*; D015416:Maillard Reaction; D008956:Models, Chemical; D009844:Oligosaccharides / Q000138:chemical synthesis*; D020027:Pyrococcus furiosus / Q000737:chemistry* / Q000201:enzymology; D012680:Sensitivity and Specificity; D013696:Temperature; D001617:beta-Glucosidase / Q000737:chemistry* / Q000378:metabolism
D006027:Glycosides; D009844:Oligosaccharides; D001617:beta-Glucosidase; D007785:Lactose