Trimethionine

Trimethionine (Met-met-met) is an orally active tripeptide substrate of peptide transport systems. Trimethionine interacts with the triple-leucine-triple-threonine transport system and the oligopeptide permease (Opp) system in Escherichia coli, competing for uptake and transport processes. Trimethionine antagonizes the toxicity of threonine tripeptide and ornithine tripeptide, and competes with peptide-supported growth and amino acid source utilization processes in Escherichia coli strains. Trimethionine is taken up by Candida albicans via a carrier-mediated, energy-dependent manner, and is subsequently hydrolyzed into free methionine intracellularly. Trimethionine can be used in studies related to Candida albicans infections^[3]. In Vitro:Trimethionine competes with trileucine for utilization by the Opp⁺ and Opp^- strains of Escherichia coli K-12 TD-V, indicating that it can be recognized by the trileucine-threonine transport system^[1].
Trimethionine can be transported via the general oligopeptide transport system (Opp) in Escherichia coli W M-26-26, as it alleviates triornithine toxicity through competitive uptake inhibition^[1].
Trimethionine competes with tetra-lysine for utilization in Escherichia coli W M-26-26, confirming that it is a substrate of the general oligopeptide transport system (Opp)^[1].
Trimethionine is taken up by Candida albicans WD 18-4 via a saturable, energy-dependent carrier-mediated system; upon uptake, it is rapidly hydrolyzed to free methionine by intracellular peptidases immediately^[3].
The transport system for Trimethionine in Candida albicans WD 18-4 is highly specific, and it strongly recognizes tripeptides with hydrophobic side chains, an N-terminal acetyl group, or a D-type residue at the first position^[3]. In Vivo:Trimethionine (3.00% (methionine level in nitrogen source); diet feeding; daily; 14 days) delivered via a SPI-based diet achieves a significantly high protein efficiency ratio (3.21) and supports healthy growth in young male Wistar rats over 14 days^[2].