Million-Nasse’s reaction is specific for the amino acid:
Tryptophan
Tyrosine
Phenylalanine
Arginine
Millon’s Test: The phenol group  of phenylalanine and tyrosine containing proteins, when heated with mercuric sulfate in sulfuric acidand sodium nitrite (or, mercurous and mercuric nitrates in nitric acid) form red colored mercury phenolate.
Reference: Vasudevan 7th  ed, pg 31