NIU Department of
Chemistry & Biochemistry
Where the study of matter...matters!
Office: La Tourette Hall 425
Phone: (815) 753-6955
Research Associate, University of Maryland, College Park, 1998-2000
Ph.D., Case Western Reserve University, 1998
M.S., Moscow State University, 1992
Bioanalytical mass spectrometry; thermochemistry of non-covalent binding, gas-phase ion reactivity and energetics; characterization of protein modifications.
Coupling of ion-molecule reactions to liquid chromatography on a quadrupole ion trap mass spectrometer. Pyatkivskyy, Y.; Ryzhov, V. (2008) Rapid Commun. Masss Spectrom., 22: 1288-1294.
Identification of the Tyrosine Nitration Sites in Human Endothelial Nitric Oxide Synthase by Liquid Chromatography-Mass Spectrometry. Zickus, M.; Fonseca, F.V.; Tummala, M.; Black, S. M.; Ryzhov, V. (2008) Eur. J. Mass Spectrom., 14: 239-248.
Studying the S-nitrosylation of model peptides and eNOS protein by mass spectrometry. Taldone, F. S.; Tummala, M.; Goldstein, E. J.; Ryzhov, V.; Ravi, K.; Black, S. M. (2005) Nitric Oxide, 13: 176–187.
Probing the stability and structure of metalloporphyrin complexes with basic peptides by mass spectrometry. Jellen, E. E.; Ryzhov, V. (2005) Eur. J. Mass Spectrom., 11: 65–72.
Fundamentals of biomolecule analysis by electrospray ionization mass spectrometry: An instrumental analysis laboratory experiment. Weinecke, A.; Ryzhov, V. (2005) J. Chem. Educ., 82: 99–102.
Using collision-induced dissociation with corrections for the ion number of degrees of freedom for quick comparisons of relative bonding strength. Vinokur, N.; Ryzhov, V. (2004) J. Mass Spectrom., 39: 1268–1274.
Binding of metalloporphyrins to model nitrogen bases: Collision-induced dissociation and ion-molecule reaction studies. Hayes, L. A.; Chappell, A. M.; Jellen, E. E.; Ryzhov, V. (2003) Int. J. Mass Spectrom., 227: 111-120.
Effects of size of noncovalent complexes on their stability during collision-induced dissociation. Jellen, E. E.; Chappell, A. M.; Ryzhov, V. (2002) Rapid Commun. Mass Spectrom., 16: 1799-1804.
Mass spectrometry is a very powerful tool for solving a wide variety of problems in different areas of chemistry. Modern techniques such as electrospray ionization (ESI) allow researchers to examine very complex and fragile biomolecules, or even non-covalent complexes, in the gas phase by converting them into ions. These biomolecular ions can then be studied and manipulated within ion-trap mass spectrometers.
We are interested in studying the thermochemistry of non-covalent interactions--for example, the strength of the iron-histidine bond (heavy dotted line) shown in the structure below:
One way to characterize the bond strength in systems like this is to study simpler or model systems. For instance, the protein shown above could be replaced by a histidine-containing peptide or a volatile histidine analogue like 4-methyl-imidazole. An ion A+, such as the heme cation, can react with the model compound M in the gas phase, to form the non-covalent complex A+M, as shown in the following equation:
By studying the association, dissociation, or equilibrium, we can learn about the binding energy of systems like these. In addition to experimental approaches, we are taking advantage of semi-empirical and ab initio calculations of geometry and binding energies.
We are also interested in gas-phase ion chemistry and energetics. Our group is working on developing new experimental applications of ion-molecule reactions, as well as selective cleavage of biomolecules in the gas phase.
Another direction in our research makes use of liquid chromatography/mass spectrometry (LC/ESI-MS) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS to identify sites of post-translational and chemical modification in proteins. We are collaborating with several other research groups to solve interesting biochemical problems involving modified proteins.