CONOTOXIN MI(B) ANALOG

PURPOSE:Specific aminoacids which constitute conotoxin MI(B) are linked in a specific order to obtain the titled substance, which is suitable for use as a muscle relaxant, becase it has mederated physiological action of conotoxin MI(B). CONSTITUTION:The objective peptides of formula I, II or III are obtained by using aminoacids selected from the group consisting of L-glycine (Gly), arginine (Arg), cysteine (Cys), Histidine (His), Proline (Pro), lysine (Lys), aspargine (Asn), tyrosine (Tyr), serine (Ser), ornithine (Orn), norleucine (Nle) and by appropriate combination of protection and deprotection of amino group, carboxyl groups and side-chain functional groups, usual stepwise elongation, and fragment condensation which are customarily applied to peptide synthesis.