Applications of LC/MS in structure identifications of small molecules and proteins in drug discovery

Abstract

With advancements in ionization methods and instrumentation, liquid chromatography/mass spectrometry (LC/MS) has become a powerful technology for the characterization of small molecules and proteins. This article will illustrate the role of LC/MS analysis in drug discovery process. Examples will be given on high-throughput analysis, structural analysis of trace level impurities in drug substances, identification of metabolites, and characterization of therapeutic protein products for process improvement. Some unique MS techniques will also be discussed to demonstrate their effectiveness in facilitating structural identifications.

Orbitrap mass spectrometry: Instrumentation, ion motion and applications

“…The LTQOrbitrap has also been used to analyze intact small (3-10 kDa) (Bredehöft, Schänzer, & Thevis, 2008;Thevis et al, 2006a;Thevis, Thomas, & Schänzer, 2008b), medium (10-25 kDa) (Macek et al, 2006;Waanders, Hanke, & Mann, 2007) and large ($150 kDa) (Zhang & Shah, 2007) proteins where the MS n capability of the LIT coupled with the high performance features of the orbitrap can facilitate unambiguous determination of the charge states of fragment ions, as well as identification of PTMs by database searching. The high performance attributes of this hybrid mass spectrometer have also found applications in environmental chemistry (Barceló & Petrovic, 2007;Krauss & Hollender, 2008), drug and metabolite analysis (Breitling, Pitt, & Barrett, 2006;Cuyckens et al, 2008;Ding et al, 2007;Karu et al, 2007;Li et al, 2007a;Lim et al, 2007Lim et al, , 2008Madalinski et al, 2008;Nielen et al, 2007;Peterman et al, 2006;Ruan et al, 2008;Thevis et al, 2005;Thevis, Kamber, & Schänzer, 2006b;Thevis, Krug, & Schänzer, 2006c;Thevis et al, 2006dThevis et al, ,e, 2007aThevis et al, , 2008aZhu et al, 2007), lipidomics (Davis et al, 2008;Ejsing et al, 2006;Schwudke et al, 2007;Silipo et al, 2008), small-molecule (Chen et al, 2007b) and reaction product (Jamin et al, 2007) identification, as well as molecular structure characterization using hydrogen/deuterium exchange measurements (Chen et al, 2007a;...…”

An introduction to liquid chromatography–mass spectrometry instrumentation applied in plant metabolomic analyses

“…The sample is introduced either by manual direct infusion (DI) or via HPLC or UHPLC followed by DI, following which the sample is delivered to the probe via a capillary; the probe functions to translocate the liquid sample from the capillary to the needle of the ion source. Two ionisation sources are generally employed in LC-MS based metabolomics: electrospray ionisation (ESI) is the most commonly employed (Tolstikov et al, 2003;Jander et al, 2004;von Roepenack-Lahaye et al, 2004;Vorst et al, 2005;Moco et al, 2006;Rischer et al, 2006;De Vos et al, 2007;Hanhineva et al, 2008) and is particularly well suited to the ionisation of a wide range of metabolites including, drug compounds (Chen et al, 2007), amino and organic acids Figure 3. The relationship between column stationary phase particle size, fl ow velocity and the height equivalent to the theoretical plate (HETP) value as an expression of chromatographic separation effi ciency.…”

Isolation and Characterization of a Novel Saponin From Rosmarinus Officinalis L. (Lamiaceae).

“…The LCMS analysis provides the molecular weight information for the components of the extract. MS dissociations give further structural information on the target compounds (Chen et al, 2007). Therefore, the combination of HPLC and MS facilitates rapid and accurate identification of chemical compounds in medicinal herbs, especially when a pure standard is unavailable.…”