L-TYROSINE 4-NITROANILIDE H-TYR-PNA Tyrosine-p-nitroanilide L-Tyrosine 4-nitroanilide≥ 99% (HPLC) L-Tyr-pNA L-Tyrosine p-nitroanilide (2S)-2-amino-3-(4-hydroxyphenyl)-N-(4-nitrophenyl)propanamide Benzenepropanamide, α-amino-4-hydroxy-N-(4-nitrophenyl)-, (αS)-