抄録
The antituberculous peptide capreomycin (Cpm), isolated from Streptomyces capreolus, is composed of four congeners, Cpm IA,IB, IIA, and IIB. The structure of Cpm was first proposed by Bycroft et al. in 1971. However, since we could not agree with it on the analogy of the structure of the similar antibiotics tuberactinomycin (Tum) group, we investigated the structure of Cpm by means of NMR analysis and chemical degradacions. From the results of the comparative study on the NMR spectra of Cpm and Tum, the structures in the cyclic peptide moieties of Cpm IA and IB were newly proposed. The β-Lys residue as a branched part was determined to be linked at β-amino group of Dpr^3 residue from the results of Edman degradation and detection of β-DNP-Dpr in the hydrolyzates of DNP derivatives. Since this conclusion was further supported by the exact analysis of NMR, the total structure of Cpm was correctly determined. In order to confirm the proposed structure, we performed the total sytheses of Cpm IA and IB. The synthetic products were identical with the natural Cpm IA and IB respectively in all aspects. Consequently, the structure of Cpm was first clearly established.
