GLYCOPEPTIDE HAVING ANTIBACTERIAL ACTIVITY

NEW MATERIAL:A glycopeptide (substance A) obtained from active humors of silkworm, having the following properties. A molecular weight of pepetide part by amino acid analysis: 6044. Ultraviolet spectrum: the maximum absorption at 273nm. Composition ratio of amino acids: Asp 3, Thr 2, Ser 10, Gln 9, Gly 9, Ala 4, Val 2, Ile 1, leu 2, Tyr 1, Phe 1, Lys 2, His 2, Arg 1, Pre 2. Sugar analysis by penul sulfuric acid method: positive. Easily soluble in water, insoluble in ether, etc. White powder, etc. USE:An bacterial agent effective against Gram-positive and Gram-negative bacteria. PROCESS:Active humors of silkworm are heat-treated, and centrifuged to give a supernatant liquid. It is subjected to salting-out or gel filtration, to give two fractions having antibacterial activity. The fraction having higher molecular weight is subjected to a cation exchanger. The prepared fraction is subjected to salting-out, and desalted to give a fraction having antibacterial activity. It is separated, purified, desalted, and lyophilized, to give the substance A.