Sakaguchi’s reaction is specific for
Sakaguchi’s Test for Arginine : Free arginine or arginyl residues in proteins react with alpha-naphthol and alkaline hypobromite to give bright-red color. This is due to the guanidium group.
Reference: Vasudevan 7th  ed, pg 32
Tyrosine
Proline
Arginine
Cysteine