Biological activities of melanotropic peptide fatty acid conjugates.

摘要: Four fatty acids (FA, palmitic, myristic, decanoic, hexanoic) were individually conjugated to the N-terminus of alpha-MSH fragment analog, H-Asp5-His6-D-Phe7-Arg8-Trp9-Lys10-NH2. This resulted in enhanced potency conjugates (compared unconjugated melanotropin analog) as determined lizard skin bioassay and mouse melanoma cell tyrosinase bioassay. The shorter hexanoic decanoic acid at least equipotent bioassay, whereas longer myristoyl palmitoyl analogs 100 times less active. exhibited a "creeping" bioassay-that is, peptides increased with time contact skins. These observations may be related more lipid nature these FA-conjugates. In assay, 10-100 active than or analog. Each FA-melanotropic peptide prolonged (residual) melanotropic activity both bioassays. other words, after removal from skins cells, responses still manifested for hours days thereafter. As little 1 hr cells enzyme measured 48 later. Since conjugates, but not H-[Asp5, D-Phe7, Lys10]alpha-MSH5-10-NH2, activity, conversion reversible agonists irreversible was demonstrated.