MS-681a, b, c and d, New Inhibitors of Myosin Light Chain Kinase from Myrothecium sp.

II. Physico-chemical Properties and Structure Elucidation

Abstract

MS-681a, b, c and d are new inhibitors of myosin light chain kinase produced by Myrothecium sp. They are novel octapeptides containing α-alkyl-α-amino acids and a polyamine moiety. The structures were determined by NMR and FAB-MS/MS spectral analyses of the intact peptides. Their absolute configurations were elucidated by GC analysis on a chiral column of the constituent amino acids and by chemical synthesis of the polyamine moieties.