Aliphatic Index Calculator
Calculate the aliphatic index of protein sequences. Upload a FASTA file or paste your protein sequences below to get the aliphatic index values.
Input (Protein sequences or PDB structure)
Aliphatic index
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About aliphatic index calculation
The aliphatic index indicates thermostability of globular proteins:
- • Formula: AI = X(Ala) + 2.9×X(Val) + 3.9×(X(Ile) + X(Leu))
- • X = mole percent of each aliphatic amino acid
- • Low (<70): Low thermostability
- • Moderate (70-100): Moderate thermostability
- • High (>100): High thermostability
- • Reference: Ikai (1980)
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