Ethylamine and glutamic acid are substrates of theanine synthetase.

Suc-Leu-Tyr-AMC is a fluorescent substrate for calpain I and II, papain (another cysteine protease), and is used to measure the chymotrypsin-like peptidase activity of the 20S proteasome (excitation max: 360 nm; emission max: 460 nm). Suc-Leu-Tyr-AMC can also be cleaved by the Ti protease from E. coli.

4-IPP 是巨噬细胞迁移抑制因子 (MIF) 的不可逆抑制剂。