Mar 17, 2015 – MSDG Meeting

I. Dr. Wendy Zhong

Principal Scientist, Merck Research Lab

“Top Down Approach on Low Level Unknown Determination of Therapeutic Peptides and Proteins using High Resolution FT-ICR MS platform”

II. Dr. Shannon Cornett,

Applications Development Manager, Bruker Daltonics

“New tools for extracting more information from molecules in tissue using solarix XR”

Abstract for Talk I:

MALDI imaging from tissue can open new insights into the molecular changes associated with biological state.  However, knowing how an ion distributes within the tissue is merely an entry point for extracting molecular information.  High resolution mass spectrometry can provide some degree of identifying information, particularly for smaller molecules where a unique formula id can usually be established from accurate mass.

Identifying larger molecules presents even greater challenges that require other tools and strategies which we are actively developing.  For molecules up to several hundred Daltons in mass (i.e. lipids and small peptides , new detection technologies have been implemented into solarix XR which resolve the isotopic fine structures (IFS).  With IFS information it is possible to count the number of heteroatoms in the molecule which can allow unambiguous formula identification when accurate mass alone, is not sufficient.

Large proteins are typically outside the typical detection range of solarix but, using on-tissue digestion, solarix XR can image tryptic peptides as proxies to the parent protein distributions.  Protein identification directly from tissue does not offer high numbers of ids but with imageID strategies hundreds of proteins identified by high-performance qTOF can be matched with high resolution solarix XR ion images.  Using these tools a greater amount of information can be extracted from complex samples with minimal extra effort.

Abstract for Talk II:

Therapeutic peptides and proteins have become a rapidly increasing sector of today’s pharmaceutical market. However, peptide and protein pharmaceuticals are chemically and physically unstable in nature. Degradants and impurities can be generated during manufacturing and storage, leading to inactivation or worse, to toxicological responses. Due to quality and safety concerns, the demand in analytical technologies to rigorously characterize degradants and impurities of these large and complex biomolecules has increased dramatically.

High resolution mass spectrometry plays a leading role in protein structure determination. Compared to other high resolution MS instruments such as Orbitrap and TOF instruments, a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer is particularly powerful in determining protein sequence via top down approach due to its ultra-high mass resolution and high mass accuracy capability. In this presentation, several case studies will be discussed to demonstrate the unique capabilities of ultra-high resolution in structure elucidation of impurity and degradation products in large peptides and proteins. An example of using a NanoMate/CASI (Continuus Accumulation of Selected Ion) technology coupled with ECD (Electron Capture Dissociation) to determine isomeric structures for degradation products in large peptides using a top down approach will also be elaborated. Its unique capability is to determine the low level impurity in a mixture without LC separation and isolation, which could result a very quick turnaround time. Micro to nano scale sample consumption can be readily achieved via NanoMate.