MK-777 (Acetamoren) Research Material

MK-777, also called Acetamoren (CAS 950841-87-9), is supplied as a research material related to ibutamoren (MK-677), a non-peptide growth hormone secretagogue acting at GHS-R1a. Its molecular formula C₂₉H₃₈N₄O₆S is ibutamoren’s C₂₇H₃₆N₄O₅S plus C₂H₂O, consistent with the addition of an acetyl group and with the “Acetamoren” name.

What is and is not known about this material

There is no published pharmacology for this derivative. A PubMed search for MK-777 returns no records: no binding affinity, no functional data, no pharmacokinetics, no hydrolysis or deacetylation kinetics, no metabolite identification. Everything below the parent-compound heading describes ibutamoren, not the material on this page.

An acetylated analogue would be expected to deacetylate back toward the parent, but rate, extent and whether the intact molecule has activity of its own are all unmeasured here. Treat the intact derivative and the parent as separate analytes in any method, and establish those parameters rather than assuming them.

The parent compound: ibutamoren (MK-677)

Ibutamoren is a non-peptide agonist at the growth hormone secretagogue receptor GHS-R1a, whose endogenous ligand is ghrelin.

• A defined binding site. MK-0677 binds membranes from GHS-R-expressing cells with B_max 2.0 ± 0.3 × 10⁻¹⁰ mol/mg protein, with no detectable binding to non-transfected membranes.^[1]

• Its pocket is not the only one. Adenosine acts as a partial agonist at the same receptor but binds a site distinct from the characterised MK-0677 and GHRP-6 pocket, shown by ligand binding and site-directed mutagenesis, with cross-desensitisation between the two.^[2] So GHS-R1a has more than one route to activation, which matters when interpreting a competition assay.

• High constitutive receptor activity. GHS-R1a signals substantially without ligand, and that basal activity has genetic support for physiological relevance.^[3]

Research Applications

Given the absence of characterisation data, the honest applications are the ones that would generate it:

• Deacetylation and stability studies establishing whether and how fast the derivative converts to ibutamoren.

• Comparative receptor binding of derivative against parent at GHS-R1a.^[1,2]

• Analytical method development resolving intact derivative from parent.

Analytical Documentation

Purity and identity vary by manufacturing lot. Kimera Chems does not publish a single fixed purity figure for this item; refer to the batch-specific Certificate of Analysis (COA) issued for the lot received, which reflects third-party analytical testing for that lot.

Storage & Handling

Store at controlled room temperature. Keep tightly closed. Liquid formats: do not refrigerate or freeze. Cold storage may cause the solution to cloud or precipitate. If this occurs, return to room temperature and mix until clear.

Storage guidance is a house recommendation. Analytical documentation is per-lot release testing.