Ac-Phe-Arg-Trp-Gly-NH2

Ac-Phe-Arg-Trp-Gly-NH2 is a synthetic tetrapeptide fragment corresponding to the amino acids 7 through 10 of alpha-melanocyte-stimulating hormone (alpha-MSH). It is primarily used as a pharmacological tool to investigate the structure-activity relationships of the melanocortin system. The peptide demonstrates significant interspecies variability in its activity at the melanocortin 1 receptor (MC1R); while it acts as an alpha-MSH antagonist in the lizard *Anolis carolinensis*, it is ineffective in certain amphibians and fish. In murine melanoma models, the fragment does not display intrinsic agonist or antagonist activity but significantly potentiates alpha-MSH-induced tyrosinase activity, suggesting it may act as a facilitator or positive allosteric modulator of the receptor complex.

Other names

N-acetyl-L-phenylalanyl-L-arginyl-L-tryptophyl-glycinamideAcetyl-Phe-Arg-Trp-Gly-NH2Acetyl-Phe-Arg-Trp-Gly-NH-2Acetyl-Phe-Arg-Trp-Gly-NH 2alpha-Melanocyte-stimulating hormone (7-10) fragment