Please note that:

• the amino acid sequence should be entered using one-letter-code.
• if you wish to specify a posttranslational modification known to occur on your sequence, insert its standard abbreviation or a UniProt PTM identifier, surrounded by parentheses, after the residue where it occurs.
• all whitespace, and all characters different from letters and parentheses are ignored.

Example:

DMAAAMKAVT(ACET)EQGHELSNEERNLLSVAYKNVVGARRSSW

EILNS(PHOS)PEKACSLAKTAFDEAIAELDTLNEE 

describes an acetylation of the Threonine (T) at position 10, and a phosphorylation of the Serine (S) at position 44.