Catalyzes ghrelin acylation at 'Ser-3' using preferentially octanoyl-CoA, hexanoyl-CoA and decanoyl-CoA as acyl-CoA donors leading to ghrelin activity (PubMed:24045953, PubMed:18443287, PubMed:25562443, PubMed:28134508). In vitro uses also acyl-CoA donors of different lengths from short-chain (C2) to long-chain fatty acids (C16) knowing that acyl-CoA donors from butanoyl-CoA (C4) to dodecanoyl-CoA (C12) are more efficient compared to longer acyl-CoA donors, such as myristoyl-CoA (C14) and palmitoyl-CoA (C16) that are not efficient (PubMed:18443287). L-seryl-[protein] + octanoyl-CoA = CoA + O-octanoyl-L-seryl-[protein] decanoyl-CoA + L-seryl-[protein] = CoA + O-decanoyl-L-seryl-[protein] acetyl-CoA + L-seryl-[protein] = CoA + O-acetyl-L-seryl-[protein] butanoyl-CoA + L-seryl-[protein] = CoA + O-butanoyl-L-seryl-[protein] L-seryl-[protein] + pentanoyl-CoA = CoA + O-pentanoyl-L-seryl-[protein] hexanoyl-CoA + L-seryl-[protein] = CoA + O-hexanoyl-L-seryl-[protein] heptanoyl-CoA + L-seryl-[protein] = CoA + O-heptanoyl-L-seryl-[protein] L-seryl-[protein] + nonanoyl-CoA = CoA + O-nonanoyl-L-seryl-[protein] dodecanoyl-CoA + L-seryl-[protein] = CoA + O-dodecanoyl-L-seryl-[protein] L-seryl-[protein] + tetradecanoyl-CoA = CoA + O-tetradecanoyl-L-seryl-[protein] a fatty acyl-CoA + L-seryl-[protein] = CoA + O-fatty acyl-L-seryl-[protein] Inhibited by c8-acylated ghrelin mimetic peptide with an IC(50) of 22 nM (PubMed:25562443). Inhibited by 1-[2-cyano-3,12-dioxooleana-1,9(11)- dien-28-oyl] (CDDO) derivatives such as CDDO-imidazole (CDDO-Im), CDDO-methyl ester (CDDO-Me), CDDO-ethylamide (CDDO-EA), CDDO-trifluoroethylamide (CDDO-TFEA) with an IC(50) of 38 uM, 6uM, 8 uM and 44 uM respectively (PubMed:28134508). Inhibited by cyclohexenone derivatives such as 2-cyano-2-cyclohexanone and 2-bromo-2-cyclohexanone (PubMed:28134508). Inhibited by steroid derivatives such as alpha-cyanoenone steroid (PubMed:28134508). Monomer. Expressed predominantly in stomach with moderate levels in pancreas and relatively low levels in most other tissues. Not glycosylated. Belongs to the membrane-bound acyltransferase family.