ClogP Equivalent Peptide Hydrophobicity

Abstract

Bioactive peptides, e.g. neuropeptides and peptide hormones, often have post-translational modifications like C-terminal amidation or N-terminal pyro-glutamination. A new peptide ghrelin, which found in 1999, had been found that its 3rd amino acid residue serine is octanoylated. To discuss these peptides from the viewpoint of physicochemical property and activity relationship, we have no hydrophobic parameters covering these modified amino acids. We expanded ClogP calculation concept to medium-sized peptides with parameters divided into each residue contribution. These parameters can be summed up along amino acid sequences, and provide exactly the same values as those of ClogP without drawing any SMILES structural expressions. We showed two examples, thyroliberin and ghrelin calculations in this paper. This method provides a consistent way of hydrophobisity prediction from small organic compounds to large proteins. This idea named Biopolymer ClogP (BP-ClogP) can be expanded to other bio-molecules like sugar chains, glycoproteins, lipids, lipoproteins, DNA and RNA molecules.