Development of mass spectrometric methods for the analysis of components and complex interactions in biological systems.

摘要

The anti-cancer agent 4,4-dihydroxybenzophenone-2,4-dinitrophenylhydrazone (A007) forms complexes with pi-delocalized lymphangitic dyes that allow its penetration through the skin effectively delivering it to a meta-stable type cancerous site. Previous in vitro studies, combined with gas phase mass spectrometry studies, have shown that a stronger binding affinity equates to a greater efficacy of the drug. For the determination of drug:dye complex binding strength coefficients in solution, two methods have been developed by affinity capillary electrophoresis (ACE), and cation exchange liquid chromatography (CELC). The methods demonstrated that A007 non-covalent binding strength was greatest for methylene green, followed by methylene blue, and lastly toluidine blue.; Bond dissociation energies and apparent reaction enthalpies for the fragmentation pathways of lithiated acylglycerols were experimentally determined by collision activation in a triple quadrupole mass spectrometer. A developed novel derived effective path length approach for predicting bond dissociation energies (BDE) for electrostatic complex's alkali metal adducts (Li+), and halide adducts (Cl-) of acylglycerols was applied to the major fragmentation product ions of a lithiated mono-acylglycerol, a 1,2-diacylglycerol, and a 1,3-diacylglycerol, to predict the covalent bond dissociation energies involved in fragmentation pathways. The model's calculated apparent reaction enthalpies are used in conjunction with the energy-resolved mass spectrometry method of breakdown graphs to give a more complete quantitative aspect to the interpretation of the fragmentation processes. The dry eye condition affects millions of individuals world wide. The symptoms can be a result of simple irritation to the eye or a serious disease state. A dry eye model was developed using rabbits in order to study the compositional makeup of the tear components in hopes of identifying an underlying cause, or expressed effect of the dry eye condition. The major nonpolar lipids of the tear were identified by mass spectrometry as mono and diacylglycerols, with a smaller extent of triacylglycerols. The major polar phosphorylated lipids were identified in the tear extract revealing that sphingomyelin based species were being expressed in the dry eye condition. The major proteins were determined to be the lower molecular weight lipid binding proteins where two specific species were found to increase in expression for the dry eye condition.