Monensins are a series of polyether ionophore antibiotic factors produced by Streptomyces cinnamonensis. Three monensin factors and four metabolites of monensin A isolated from cattle feces were investigated by electrospray ionization mass spectrometry (ESI-MS). In-source collision-induced dissociation (CID) of the alkali metal and ammonium molecular ion adducts of monensin produce strikingly different mass spectra, with the alkali metal complexes exhibiting little dissociation and the ammoniated forms characterized by extensive fragmentation of the polyether skeletal structure with the production of several structurally diagnostic ions. The observed fragmentation of ammoniated monensin primarily involves opening of the cyclic ether rings and consecutive H 2 O losses. The propensity of ammoniated monensin derivatives toward skeletal fragmentation may involve the complexation of the thermally labile NH 4 ion through multiple hydrogen-bonding interactions with the polyether complexing oxygens resulting in decreased stability of the resultant complex. Comparison of the in-source CID spectra associated with the structurally similar compounds evaluated provides for the proposal of a general scheme for the fragmentation of ammoniated monensins and related compounds, the consistency of which indicates the usefulness of ESI-MS with insource CID in ionophore structure elucidation. # 1998 John Wiley & Sons, Ltd. Received 8 May 1998; Accepted 20 May 1998 Monensin is a polyether monocarboxylic acid ionophore and refers to a group of factors comprising an antibiotic complex first isolated from Streptomyces cinnamonensis.
The antibacterial properties of macrolide antibiotics (such as erythromycin, tylosin, and narbomycin) depend ultimately on the glycosylation of otherwise inactive polyketide lactones. Among the sugars commonly found in such macrolides are various 6-deoxyhexoses including the 3-dimethylamino sugars mycaminose and desosamine (4-deoxymycaminose). Some macrolides (such as tylosin) possess multiple sugar moieties, whereas others (such as narbomycin) have only single sugar substituents. As patterns of glycosylation markedly influence a macrolide's drug activity, there is considerable interest in the possibility of using combinatorial biosynthesis to generate new pairings of polyketide lactones with sugars, especially 6-deoxyhexoses. Here, we report a successful attempt to alter the aminodeoxyhexose-biosynthetic capacity of Streptomyces fradiae (a producer of tylosin) by importing genes from the narbomycin producer Streptomyces narbonensis. This engineered S. fradiae produced substantial amounts of two potentially useful macrolides that had not previously been obtained by fermentation.
In addition to degradation products, impurities, and exogenous contaminants, industries such as pharmaceutical, food, and others must concern themselves with leachables. These chemicals can derive from containers and closures or migrate from labels or secondary containers and packaging to make their way into products. Identification and quantification of extractables (potential leachables) and leachables, typically trace level analytes, is a regulatory expectation intended to ensure consumer safety and product fidelity. Mass spectrometry and related techniques have played a significant role in the analysis of extractables and leachables (E&L). This review provides an overview of how mass spectrometry is used for E&L studies, primarily in the context of the pharmaceutical industry. This review includes work flows, examples of how identification and quantification is done, and the importance of orthogonal data from several different detectors. E&L analyses are driven by the need for consumer safety. These studies are expected to expand in existing areas (e.g., food, textiles, toys, etc.) and into new, currently unregulated product areas. Thus, this topic is of interest to audiences beyond just the pharmaceutical and health care industries. Finally, the potential of universal detector approaches used in other areas is suggested as an opportunity to drive E&L research progress in this arguably understudied, under‐published realm.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.