Used as a chromogenic substrate in enzymatic assays, particularly for studying protease activity. The compound allows detection of enzyme action through the release of para-nitroaniline (pNA), which produces a yellow color measurable by spectrophotometry. Commonly applied in screening and kinetic analysis of serine proteases and other hydrolases involved in peptide bond cleavage. Its Boc-protected methionine structure provides specificity toward enzymes that recognize hydrophobic amino acid residues. Widely utilized in biochemical research and drug development for monitoring proteolytic reactions in a quantitative and time-resolved manner.