Fig. 5. Monitoring of reaction cycles of SEA (A) and schematic drawing of a rapid and convenient method for glycosyl azide preparation using SEA-immobilized column (B).

　(A) Reaction cycles of SEA were monitored by using pNP-X₂ as a substrate (see text for details). The amount of released pNP (open circles) was measured. (B) The C-terminal His₆-tagged SEA was immobilized onto a Ni column (I). pNP-X₂ was loaded on the SEA-immobilized column (II). Glycosyl azide was eluted by adding sodium azide (III). The procedures (II) and (III) were repeated. Detailed procedures are described in the text.