Kazuaki Higashi

Structure of angelmicin B, A novel src signal transduction inhibitor

The structure of angelmicin B, which has been found to be a specific inhibitor of tyrosine kinase and src-dependent cell transformation, was determined. Angelmicin B consists of six deoxyhexoses and eight fused six-membered rings containing highly oxidized naphthylnaphthoquinone as a chromophore.

Substrate specificity of α-L-arabinofuranosidase from Streptomyces diastatochromogenes 065 toward arabinose-containing oligosaccharides

Abstract α- l -Arabinofuranosidase from Streptomyces diastatochromogenes 065 released only the terminal arabinose of arabinoxylo-oligosaccharides. The enzyme hydrolyzed methyl arabinofuranobiosides to arabinose and methyl arabinofuranoside in the order of (1→2)>(1→3)>(1→5)-linkages. The enzyme preferentially hydrolyzed the (1→3)-linkage over the (1→5)-linkage of methyl arabinofuranotrioside.

Cutinostatin B as a New Cutinase Inhibitor Produced by Actinomycete.

Cutinostatin B was purified from a culture filtrate of a strain No. 3112-4 of an actinomycete which had been isolated from a soil sample collected in Setagaya-ku, Tokyo, Japan. The structure of this compound was determined mainly by 2D NMR experiments to be N(α)-[N(α)-(2,3-dihydroxybenzoyl)-ornithyl]-N(δ)-hydroxyornithine-δ-lactum. Cutinostatin B inhibited the cutinase activity of Cladosporium fulvum when using β-naphthyl caproate as the substrate with an IC50 value of 28.9 μm (11.0 μg/ml), and inhibited 95% when using crude apple cutin as the substrate with a concentration of 263 μM (100 μg/ml).