Table 4. Catalytic and binding activities of deletion derivatives of wild-type PK1A and mutant PK1A2 endosialidases.

The derivatives were expressed and purified as their GFP-fusion proteins, and assayed for catalytic and binding activities as described in Figures 3 and 5. Binding is defined as sustained binding, distinct from the transient binding during catalysis. Endosialidases with the deletions 1–158, 1–211, 616–811 and 565–811 were insoluble.

	Deleted sequence	Catalytic activity	Observed binding
PK1A (wild-type)	Unmodified	+	–
	Δ1–47	+	–
	Δ1–107	–	+
	Δ719–811	–	–
	Δ668–811	–	–
PK1A2 (mutant)	Unmodified	–	+
	Δ1–47	–	+
	Δ1–107	–	+
	Δ719–811	–	–
	Δ668–811	–	–