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.