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N-Methyl Amino Acids

N-Methyl amino acids can improve the pharmacokinetic properties of bioactive peptides when they replace standard amino acids. Many peptides are readily metabolized by proteolytic enzymes resulting in a short half-life in vivo.  Introducing N-methyl amino acids generally increases the enzymatic stability of peptides, thus increasing their in vivo half-life.  Most peptides either are hydrolyzed by digestive enzymes or are poorly absorbed through the intestine, resulting in poor oral availability.  Substituting in N-methyl amino acids can increase peptidase stability and enhance intestinal permeability.  Recent reports show that peptides rich in N-methyl phenylalanine passively diffuse across the blood-brain barrier and can be used as blood-brain barrier shuttles.


N-methyl amino acids, when included in peptides, can enhance activity and selectivity or convert an agonist to an antagonist.  These changes are usually attributed to reduced backbone flexibility resulting from N-methyl groups.  The N-methyl groups also inhibit hydrogen bonding, resulting in improved water solubility in hydrophobic Aβ peptides.


AAPPTec offers a large selection of Boc-N-Me-amino acids, Fmoc-N-Me-amino acids and unprotected N-methyl amino acids.  All AAPPTec N-Methyl amino acid products are available in bulk quantities.  Contact us at for a quotation for larger quantities or use the On-Line Quote Request.