Temporary deactivation technique

Demchenko and co-workers demonstrated that STaz glycosides can be engaged in stable non-ionizing transition-metal complexes. This observation served as a basis for the development of a temporary deactivation technique for oligosaccharide synthesis (Scheme 28).158 The deactivation of the otherwise reactive building block was... 

SCHEME 29. Synthesis of pneumococcal oligosaccharides serogroup 14 by temporary deactivation technique.159... 

Immobilization has other advantages it can slow enzyme deactivation by inhibiting protease attack and minimizing shear, interfacial, temperature, or solvent denaturation. As for the scarcity of some potentially very useful enzymes, it may be only a temporary problem. The development of cloning techniques, and probably the very increase in demand will result in lower prices. One spectacular instance is sialyl aldolase (see Table I). Industrial production of this enzyme by the gene-cloned strain of Escherichia coli has been reported.1,2 Sialylaldolase is now available from Toyobo at a moderate price. 

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