David Van Horn

Professor of Chemistry

Links More Information David’s Virtual Lab Contact Office: 510F Flarsheim Hall Phone: 816-235-6327 Fax: 816-235-2290 E-mail: vanhornj@umkc.edu

Current Research Interests

My interests lie in a broadly defined field termed Bioinorganic Chemistry. This area of inorganic chemistry covers a broad spectrum of topics, techniques and disciplines. Simply put, bioinorganic chemistry is the chemistry of metals interacting with biological or environmental materials and molecules. This research has a basic component and an applied component. The first concerns the fundamental biological functions of metals such as looking at catalysis and electron transport in metal containing enzymes, the structural and regulatory roles of metals, metal toxicity and the transport and storage of metals in the biological systems and the environment. On the applied side, bioinorganic chemistry concerns itself with the development of medical imaging agents, radiopharmaceuticals, biochemical probes and sensors, metal toxicity and environmental remediation.

Our lab is engaged in the study of the bioinorganic chemistry of two elements, uranium and chromium. Although these two metals exhibit quite different chemical properties, a common thread in our studies is the question of their transport and action in the bloodstream.

URANIUM

Uranium in the form of the uranyl cation (UO₂²⁺) is the form found under usual conditions in the environment. In the bloodstream, uranyl cation is complexed almost completely by carbonate; our lab is interested in describing the uranyl-peptide or uranyl protein interactions that give rise to transport of this metal ion in the blood serum. Recently, we published a paper describing interactions of the uranyl cation with a short peptides which led us to a model of non-specific transport in serum (Inorganic Chemistry, 2005). This work does not preclude the possibility of higher stability complexes between uranyl cation and peptides or proteins, and we are also looking for protein sequence specificity in uranyl-protein interactions.

CHROMIUM(III)

Millions of Americans take supplements containing chromium, usually in the form of chromium(III) [“Cr(III)”]. This is despite the fact that no one knows the exact mechanism of action for Cr(III) in the body. Our lab is interested in studying the fundamental coordination chemistry of Cr(III) as it applies to the expected forms of Cr(III) in vivo, its transport in the bloodstream, its excretion, and its potential pharmacological action in the human body. Cr(III) is thought to act in the insulin signaling pathway to enhance or sustain glucose metabolism, and Cr-peptide containing complexes have been isolated from tissue.

Our lab has completed a bioinformatics study to locate the origin of Cr(III)-peptide complexes found in the body (BMC Chemical Biology, 2004). We are also interested in studying model complexes and reactions with trinuclear and multinuclear chromium clusters. We are currently focused on the kinetics of such systems to determine the limits of the chemistry of Cr(III) in conditions that mimic biological systems.

The techniques used widely in my lab include: organic synthesis of ligands; inorganic synthesis, characterization of ligands and complexes by NMR, mass spectrometry, and other standard methods; analytical chemistry; computational modeling.