Table 1.

The 13 amino acid indices (selected from a total of 531 indices) used for characterization of tripeptides.

Index Number	Description	Reference
1	Isoelectric Point	[22]
2	Normalized van der Waals Volume	[23]
3	Alpha-Helix Indices for Beta-Proteins	[24]
4	Beta-Strand Indices for Beta-Proteins	[24]
5	Side-Chain Contribution To Protein Stability	[25]
6	The Stability Scale from the Knowledge-Based Atom–Atom Potential	[26]
7	Hydropathy Index	[27]
8	Normalized Frequency of Turn	[28]
9	Free Energy in Beta-Strand Region	[29]
10	Free Energy in Alpha-Helical Region	[29]
11	Polarity	[30]
12	Side Chain Interaction Parameter	[31]
13	Amino Acid Distribution	[32]