Structural properties and conformational stability of de novo proteins -- albebetin and albeferon (albebetin with a grafted interferon fragment) -- were studied by means of CD spectroscopy, gel filtration and urea-induced unfolding. The results allow us to conclude that albebetin possesses the properties of the molten globule state. Grafting of the octapeptide to the N-terminus of this de novo protein affects its structure. We show here that albeferon maintains a secondary structure content of albebetin; it becomes more compact and much more stable toward urea-induced unfolding as compared to albebetin and even possesses some weak tertiary structure (at least around Tyr7). This means that the structure of the artificial protein albebetin can be improved by a simple procedure of octapeptide grafting to its N-terminus.