Using 8 web-algorithms, including Pasta2, AmylPred2, Tango, MetAmyl, Waltz, Aggrescan, BetaScan та FoldAmyloid, theoretical analysis of amino acid sequences of lysozyme, cytochrome c and N-terminal fragment of apolipoprotein A-I has been carried out, and amyloidogenic fragments of the proteins have been identified. The fragment was identified as amyloidogenic if it was determined by at least four algorithms. Comparative analysis of aggregation-prone regions of native and mutant proteins showed that that all mutants are characterized by same amyloidogenic segments as native proteins with the amyloidogenic potential being more pronounced for mutated proteins. It was shown that aggregation-prone regions of all proteins analyzed here, were rich in hydrophobic aliphatic (Ile, Val, Leu, Ala) and aromatic (Trp, Phe, Tyr) amino acid residues. Hydrophobic interactions were supposed to play key role in protein aggregation process.