Table 2. Detailed description of the internal His-tagged IFN variants showing the localisation of His-tag insertion, sequence of the His-tag and native amino acids that were replaced.

IFN	PEG-tag location	His-tag sequence	Original IFN amino acids
5(HGH)-IFN	5	HGH	QTH
34(HGHG)-IFN	34	HGHG	HDFG
106(HGHG)-IFN	106	HGHG	T-ET
120(HHH)-IFN	120	HHH	RKY
134(HGHG)-IFN	134	HGHG	K-YS