33 ブラストサイジンSの撰択的拮抗物貭デトキシンの化学的研究

抄録

The selective antagonists of blasticidin S elaborated by Streptomyces griseo-chromogenes var. detoxicus containing up to twenty congeners are classified into eight groups designated detoxins A to H. Detoxins show several interesting biological activities counteracting to the toxicity of blasticidin S against plant and animal cells. The separation of detoxin complex into eight groups was achieved by bufferized ion exchange resinchromatography (Dowex 50W X2, 0.2 M pyridine-acetate buffer at pH 5.0), and detoxin D group, which could be further separated into detoxins D_1, D_2 and D_3, was one of the most active component. Detoxin D_1, C_<28>H_<41>N_3O_8, mp. 156-158℃, [α]^<25>_D-16°(c 1, in methanol) is an amphoteric compound with pKa 4.0 and 8.0 and shows positive ninhydrin reaction. Acid hydrolysis of detoxin D_1 afforded (+)-2-methylbutyric acid, L-valine, L-phenylalanine and an unknown amino acid designated detoxinine. The N-terminus was determined to the amino group of L-valine by DNP and diazotization methods. Partial alkaline hydrolysis of detoxin D_1 gave valyl-detoxinine C_<12>H_<22>N_2O_5 and valyl-detoxininolactone C_<12>H_<20>N_2O_4 which were characterized as the corresponding acetates. NMR spectra together with spin decoupling experiments of the acetates of these key compounds provided the evidences on the structure of unknown amino acid detoxinine and lead to the elucidation of total structure of detoxin D_1. Application of Klyne's lactone sector rule to valyldetoxininolactone deutero-acetate gave the proof of absolute structure of detoxin D_1. The structural relationship between detoxin D_1, D_2 and D_3 was clarified and some arguements concerning the structure of detoxin C group will be presented.