title: The acetylation of the amino groups of Laticauda semifasciata III, a sea snake venom component.
abstract: The amino groups of Laticauda semifasciata III (LsIII) purified from the venom of a sea snake, Laticauda semifasciata, were acetylated with acetic anhydride. Three monoacetyl derivatives of LsIII, namely, [1-N2-acetyl-arginine]-LsIII, [23-N6-acetyl-lysine]-LsIII and [35-N6-acetyl-lysine]-LsIII, were obtained. These monoacetyl derivatives of LsIII showed the same CD spectra as that of native LsIII. [1-N2-Acetyl-arginine]-LsIII was half as active as the original toxin suggesting the importance of the net positive charge of the toxin molecule for the toxicity. [23-N6-Acetyl-lysine]-LsIII and [35-N6-acetyl-lysine]-LsIII showed no toxicity. Lysine-23 is one of the residues common to all neurotoxins, whereas lysine-35 is one of the residues found specifically among long-chain neurotoxins, although there are some exceptional toxins without lysine-23 or lysine-35.
mesh_terms: D000107:Acetylation; D000818:Animals; D002942:Circular Dichroism; D004546:Elapid Venoms / Q000633:toxicity*; D007928:Lethal Dose 50; D051379:Mice; D009498:Neurotoxins; D010446:Peptide Fragments / Q000633:toxicity; D011506:Proteins / Q000633:toxicity*; D030162:Reptilian Proteins; D013329:Structure-Activity Relationship; D014357:Trypsin
chemical_list: D004546:Elapid Venoms; D009498:Neurotoxins; D010446:Peptide Fragments; D011506:Proteins; D030162:Reptilian Proteins; C027050:Laticauda semifasciata III; D014357:Trypsin