Profiling of isovalertatin family aminooligosaccharides extracted from theculture of Streptomyces luteogriseus by using liquid chromatography/electrospray ionization mass spectrometry

A rapid and novel procedure using the liquid chromatography coupled to an e lectrospray ionization ion trap mass spectrometry technique was applied for the profiling of isovalertatin-family aminooligosaccharides in the extract from the culture filtrate of Streptomyces luteogriseus. The aminooligosacc harides were separated on a C-8 reversed-phase column with an acetonitrile- alkaline water gradient. The desired homologues were detected using the mul tiple reaction monitoring mode, and the chemical structures were confirmed by analyzing the characteristic fragment ions in their collision-induced di ssociation spectra. This facile procedure led to the identification of all the five known aminooligosaccharides, isovalertatins M03, M13, M23, D03, an d D23, in addition to the characterization of at least 41 novel isovalertat ins, the molecular weights of which ranged from 729 to 2793. This kind of a ssay should be intended as a simple and convenient way for the high-through put analysis of screening aminooligosaccharides and potentially other struc tural families of natural products.