One-Letter to Three-Letter Amino Acids

Protein sequences

SeparatorResidues per line

Output

How to convert one-letter to three-letter amino acid codes

Paste a protein sequence in one-letter codes.
Choose the separator (none, a space or a hyphen) and how many residues to put on each line.
Each letter becomes its three-letter code, such as Met for M. Copy output or Download saves the result.

Frequently asked questions

What happens to * and X?

A stop (*) becomes Ter and X becomes Xaa. B, Z, J, U and O become Asx, Glx, Xle, Sec and Pyl.

Is my sequence uploaded?

No. Everything runs in your browser, so your sequences never leave your device.

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