PURIFICATION AND CHARACTERIZATION OF AN EXTRACELLULAR ENZYME FROM STREPTOMYCES-ANTIBIOTICUS THAT CONVERTS INACTIVE GLYCOSYLATED OLEANDOMYCIN INTO THE ACTIVE ANTIBIOTIC
Lm. Quiros et al., PURIFICATION AND CHARACTERIZATION OF AN EXTRACELLULAR ENZYME FROM STREPTOMYCES-ANTIBIOTICUS THAT CONVERTS INACTIVE GLYCOSYLATED OLEANDOMYCIN INTO THE ACTIVE ANTIBIOTIC, European journal of biochemistry, 222(1), 1994, pp. 129-135
Cell-free extracts from the oleandomycin producer, Streptomyces antibi
oticus, possess an intracellular glycosyltransferase capable of inacti
vating oleandomycin by glysosylation of the 2'-hydroxyl group in the d
esosamine moiety of the molecule [Vilches, C., Hernandez, C., Mendez,
C. and Salas, J.A. (1992) J. Bacteriol. 174, 161-165]. Using a four-st
ep purification procedure, we have purified an enzyme activity from th
e culture supernatants from this organism which is able to release glu
cose from the inactive glycosylated molecule thus reactivating the ant
ibiotic activity. This enzyme activity appeared in the culture superna
tants immediately before oleandomycin is detected. The enzyme (molecul
ar mass 87 kDa) showed a high degree of substrate specificity, not act
ing on other glycosylated macrolides such as methymycin, lankamycin an
d rosaramicin which are substrates for the glycosyltransferase. A seco
nd activity was detected corresponding to a 34-kDa polypeptide which p
robably originates from proteolytic cleavage of the larger polypeptide
. The 87-kDa polypeptide possibly catalyses the last biosynthetic step
in oleandomycin biosynthesis by S. antibioticus.