H-Ala-Ala-OH

H-Ala-Ala-OH is a substrate of human intestinal oligopeptide transporter (PEPT1/SLC15A1), with an IC₅₀ of 0.25 mM and an EC₅₀ of 0.08 mM against human PEPT1. When used as a dipeptide linker in antibody-drug conjugates (ADCs) loaded with glucocorticoid receptor regulator payloads, H-Ala-Ala-OH enables efficient intracellular payload release^[1][2][3].
In Vitro:The ADC containing H₂Ala-Ala-OH (Ala-Ala) as the dipeptide linker potently activates the GRE luciferase reporter in mTNF-overexpressing K562 cells with an EC₅₀ of 0.92 μg mL⁻¹, and shows no activity in wild-type K562 cells, confirming targeted activity^[1].
H-Ala-Ala-OH (0.08-5 mM; 2 min) acts as a highly potent PEPT1 substrate in MDCK-PEPT1 cells, with an EC₅₀ of 0.08 mM and a %GSmax of 125%, resulting in a %GSmax/EC₅₀ ratio of 1700 that classifies it as one of the best PEPT1 substrates tested^[2].
H-Ala-Ala-OH (0.1-9 mM; 30 min preincubation, 10 min uptake period) binds to PEPT1 in MDCK-PEPT1 cells with an IC₅₀ of 0.25 mM, confirming it interacts with the transporter's binding pocket^[2].
H-Ala-Ala-OH exhibits a favorable low-energy conformation for PEPT1 binding and transport in silico, with flexible small side chains enabling ideal interaction with the transporter's binding pocket^[2].
H-Ala-Ala-OH (0.010-100 mM; 30 min) potently inhibits hPEPT1-mediated ³H-Gly-Sar uptake in CHO-PEPT1 cells with an IC₅₀ of 0.063 mM^[3].