Nonapeptide-1 (Melanostatine-5) acetate salt, a peptide hormone, is a selective antagonist of MC1R (Ki: 40 nM). Nonapeptide-1 acetate salt is a competitive α-MSH antagonist that effectively inhibits α-MSH-induced intracellular cAMP and melanosome diffusion in melanocytes (IC50= 2.5 nM and 11 nM, respectively). Nonapeptide-1 acetate salt inhibits melanin synthesis and may be utilized to study skin pigmentation, regulation of adrenal steroidogenesis, and skin cancer.

Physicochemical Properties

Molecular Formula	C63H91N15O11S
Molecular Weight	1266.56
Related CAS #	Nonapeptide-1;158563-45-2
Appearance	White to off-white solid powder
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

Targets	MC1R MC3R 0.47 μM (Ki) MC4R 1.34 μM (Ki) MC5R 2.4 μM (Ki)
ln Vitro	Nonapeptide-1 acetate salt(153N-6) has an IC50 value of 11 nM and inhibits the dispersion of melanosomes caused by α-melanocyte hormone (α-MSH). Melanocytes exposed to α-MSH-induced intracellular cAMP levels are inhibited by nonapeptide-1 acetate salt (0.1 nM-1 μM, 30 min), with an IC50 of 2.5 nM[1]. Nonapeptide-1 acetate salt (153N-6) is preferential for MC1R over MC3R, MC4R, and MC5R (Ki: 0.47, 1.34, and 2.4 μM, respectively) and has the highest affinity for MC1R (Ki: 40 nM) in COS-1 cells expressing human receptors[2]. Human epidermal melanocytes (HEM cells) and HaCaT cells are treated with nonapeptide-1 acetate salt (N-1A, 20 μM, 3 days) to decrease basal melanin synthesis and reverse UVA-induced melanin increase[3]. Nonapeptide-1 acetate salt (20 μM, 3 days) binds to MC1R in HaCaT and HEM cells, competing with α-MSH to downregulate the expression of MC1R, tyrosinase, TRP1, TRP2, and MITF[3].
Cell Assay	Western Blot Analysis[3] Cell Types: HaCaT cells, Human epidermal melanocytes(HEM) Tested Concentrations: 20 μΜ Incubation Duration: 3 days Experimental Results: Downregulated the expression of MC1R, tyrosinase, TRP1, TRP2, and MITF.
References	[1]. Discovery and structure-function analysis of alpha-melanocyte-stimulating hormone antagonists. J Biol Chem. 1994 Nov 25;269(47):29846-54. [2]. Characterization of the binding of MSH-B, HB-228, GHRP-6 and 153N-6 to the human melanocortin receptor subtypes. Neuropeptides 31(6), 565-571 (1997). [3]. Effects of tea polyphenols on UVA-induced melanogenesis via inhibition of α-MSH-MC1R signalling pathway. Postepy Dermatol Alergol. 2022 Apr;39(2):327-335.

Solubility Data

Solubility (In Vitro)	H2O :~50 mg/mL (~39.48 mM)
Solubility (In Vivo)	Solubility in Formulation 1: 50 mg/mL (39.48 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with sonication.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	0.7895 mL	3.9477 mL	7.8954 mL
	5 mM	0.1579 mL	0.7895 mL	1.5791 mL
	10 mM	0.0790 mL	0.3948 mL	0.7895 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.