... Standards: FCC4,AJI92,USP26,EP4 L-ThreonineIndications and UsageThreonine (abbreviated as Thr ... to an aromatic ring, giving it different acid/base and oxidative properties).The threonine residue is susceptible ... (2S,3S) and (2R,3R). However, the name L-threonine is used for one single enantiomer, (2S,3R ... ), which is rarely present in nature, is called L-allo-threonine. The two stereoisomers (2R,3S)- and ...