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44216-B4
A Characterization of the Kinetics and Mechanisms of the Reaction of Ribose 5-Phosphate and Amino Acids
I. Research Progress
Over the past year, the diligent efforts of five undergraduate researchers (along with the time I could spend on the project while on sabbatical leave) brought an improved understanding of the unique reactions of R5P with amines in the early steps of the Maillard process. The thorough analysis of the kinetics of the reaction was completed and a correlation of the speed of the reaction to the pKa of the attacking amine onto the sugar nucleus was identified. A comparison of the R5P reaction kinetics to that of a non-phosphorylated sugar (ribose) and to a non-traditional Maillard-reacting sugar (deoxyribose 5-phosphate, dR5P) helped to clarify an explanation for why R5P reacts more rapidly than most other sugars and sugar phosphates. Identification of reaction products, both expected and unexpected, was performed using a combination of liquid chromatography-mass spectroscopy (LC/MS) and nuclear magnetic resonance (NMR) spectroscopy. [The acquisition of a new Agilent LC/MS instrument in early 2006 through funds from a NSF Major Research Instrumentation (MRI) was of great benefit to our research progress.] In regard to the identification of products, it is worthy of note that two unique reaction products were identified in the dR5P reaction system.
During the year, funds from the PRF grant were instrumental in procuring supplies required in carrying out the research and for offering stipends (summer, 2007) for two undergraduate students.
Future Research: Our next step in the investigation is to look at the question of why the attach phosphate promotes the kinetics of the R5P reaction. Our recent work with the dR5P system (and an arabinose phosphate system) was partially helpful in this regard; however our investigation requires that we clearly identify the contribution of the phosphate in causing the more reactive acyclic sugar form. (This will thus separate the acyclic effect from the catalytic role the phosphate may be playing as a general acid/base.) To answer this question we will need to synthesize both the methyl ester (to the phosphate) form and the 5-deoxy form of R5P and then perform comparable kinetics studies of these modified sugars. We are also pursuing a characterization of R5P's ability to generate reactive oxygen species during the Maillard reaction. This has important implications on the reaction path of the molecule and of physiological consequences of R5P in this reaction in biological fluids.
II. Development of Undergraduate Researchers
In various ways, the PRF grant support of this project has significantly impacted the development of five Middlebury College B.A. Biochemistry undergraduates during the timeframe Sept. 1, 2006 – Aug. 31, 2007. Admire Munanairi and Steven O'Banion were honors thesis students working on Maillard reaction projects during the 2006 – 2007 academic year. Both successfully completed his thesis and presented a campus seminar on the work in April, 2007. Mr. Munanairi subsequently entered a graduate program in Biochemistry at Washington University in St. Louis while Mr. O'Banion has taken a job with Ambit Biosciences in San Diego with plans to enter graduate school in biochemistry in Fall, 2008.
In summer, 2007, funds from the PRF grant provided stipends and supplies for two undergraduate researchers, Andrew Harris and Caitlin King, for a ten-week period. Mr. Harris, a senior Molecular Biology and Biochemistry major, will continue his Maillard research studies as part of senior honors thesis in the 2007 – 2008 academic year. His experience will benefit him in his future plans in either an M.D. or M.D/Ph.D. program. Ms. King, currently a second year student, will continue to pursue research part-time during the academic year. She has recently declared her major as Molecular Biology and Biochemistry and will pursue an honors thesis when she reaches her senior year. In addition, Andrew Livermore, a summer research student sponsored by the Vermont Genetics Network, was aided in his Maillard studies by the interactions he had with the two PRF-supported students.
III. Professional Growth of the PI
The PI has been greatly aided by PRF support of this project. Besides helping him to develop the research skills of undergraduates destined for careers in chemistry or medicine, the support has enabled him to develop professionally to become one of the active scholars in this line of Maillard research. Over the past year, he has given several presentations on this research at other institutions. In late August/early September, 2007, support from the PRF grant allowed the PI to attend and present a poster at the 9th International Symposium on the Maillard Reaction (held in Munich, Germany) – the single most important meeting of Maillard research attended by most of the acknowledged experts of the field. (It is held every two or three years.) The meeting and the contact with experts in the Maillard field was an extremely valuable experience for the PI.
