The Reactive Site of Marinostatin, a Proteinase Inhibitor from Marine Alteromonas sp. B-10-31

Abstract

A new homologue of marinostatin, a peptide proteinase inhibitor, was isolated from marine Alteromonas sp. B-10-31 and designated as marinostatin D. Its amino acid sequence was determined to be Ala-Thr-Met-Arg-Tyr-Pro-Ser-Asp-Asp-Ser-Glu. The reactive site of marinostatin D was determined to be Met(3)-Arg(4) on the basis of the reversible cleavage and regeneration of the scissile bond catalyzed by TLCK-chymotrypsin.