2012- 21st Annual NC State Undergraduate Research Symposium

Session Time : 4/10/12 12:15 PM - 4/10/12 1:30 PM

Content Area : Chemistry

Poster Appointment: , -

Student Presenters :
Amber D Taylor Chemistry

Mentors and/or Co-Authors :
David Muddiman Chemistry
Steven Walker Chemistry

Abstract Title : Aniline catalyzed hydrazone formation for the derivatization of N-linked glycans

Abstract :
The development of hydrophobic hydrazide reagents has afforded several advantages for the ESI-MS analysis of N-linked glycans: 1) increased ESI efficiency and ion abundance in the MS, 2) the ability to incorporate stable isotopes onto the reagents for mass differentiation and relative quantification of N-linked glycans, and 3) the ability to retain and separate N-linked glycans on a C₁₈ reverse phase chromatography platform. The near stoichiometric reaction efficiency has been demonstrated previously; however, the reaction conditions are at elevated temperatures and low pH. This has been shown to cause partial degradation of sialic acid residues at an incidence of up to 15%. It is hypothesized that using an aniline catalyst can speed up the reaction at ‘near physiological conditions,’ and allow for several important advantages such as decreased degradation, the decrease in reaction time, and the ability to use less excess tagging hydrazide reagent. It is shown that aniline is capable of catalyzing the reaction of hydrazide reagents with N-linked glycans, both simple (linear) and complex (branched). Additionally, the optimization via a fractional factorial design is performed in order to determine the most productive reaction conditions such as pH, temperature, reaction time, reagent excess, and catalyst concentration. Using the optimized reaction conditions, the aniline catalysis method will be compared to the non-catalyzed tagging strategy in order to determine the better method for the hydrazone formation reaction of N-linked glycans.