[D-Ala2] Met-Enkephalin is a five-residue analog of Met-Enkephalin in which Gly2 is replaced by D-alanine. This single stereochemical modification changes susceptibility to peptide-degrading enzymes while retaining the Tyr-X-Gly-Phe-Met opioid recognition scaffold.

Product Information

A Single Stereochemical Change

Native Met-Enkephalin contains Gly at position 2. Substitution with D-Ala introduces both a methyl side chain and defined D-stereochemistry near the N-terminal Tyr that is critical for opioid-receptor recognition.

This compact modification provides a useful model for studying how stereochemistry changes receptor activity and enzymatic stability without altering the remaining three residues.

Improved Resistance to Peptide Degradation

Enkephalins are rapidly degraded by brain and peripheral peptidases. D-amino-acid substitution around the N-terminal region has long been used to reduce susceptibility to enzymatic cleavage.

Historical studies of D-Ala-containing enkephalin analogs demonstrated markedly greater persistence than native Met-Enkephalin in peptide-degradation systems.

Opioid Receptor Research

[D-Ala2] Met-Enkephalin is used as an opioid agonist in receptor and neuroendocrine studies. Its pharmacology should not be described as absolutely selective for a single opioid receptor subtype because receptor profile depends on the precise analog, assay and species.

Analytical Considerations

The C-terminal methionine can undergo oxidation, making LC-MS useful when comparing fresh and stored preparations.

Custom enkephalin analogs and D-amino-acid substitutions can be evaluated through Chemical Peptide Synthesis.

Frequently Asked Questions

Which residue is modified?

Gly2 of native Met-Enkephalin is replaced by D-Ala.

Is the peptide C-terminally amidated?

No. The listed sequence ends in Met with a free carboxyl terminus.

Research Use Only.