Enzymes in oligosaccharide synthesis: active-domain overproduction, specificity study, and synthetic use of an .alpha.-1,2-mannosyltransferase with regeneration of GDP-Man
摘要:
The catalytic domain of a membrane-bound alpha-1,2-mannosyltransferase (ManT) from yeast has been overexpressed in E. coli, at a level of approximately 0.7-0.8 units per L with a specific activity of about 1 U/mg (based on a-methyl mannoside) after purification. The E. coli strain has been deposited in ATCC (#77379) and will be available to the public. The isolated ManT is stable in 30% methanol or 20% acetone. It accepts mannose, mannobiose, and O-mannosylglycopeptides as acceptors. A multiple enzyme system with in situ regeneration of GDP-mannose suitable for large-scale synthesis of mannosides and mannosyl glycopeptides has been developed.