Interaction of L-cysteine with selenious and selenic acids: A study by the density functional theory method

• Published in: Journal of structural chemistry 2010-02, Vol.51 (1), p.9-15
• Main Authors: Pankratov, A. N., Bychkov, N. A., Tsivileva, O. M.
• Format: Article
• Language: English
• Subjects: Atomic; Atomic/Molecular Structure and Spectra; Chemistry; Chemistry and Materials Science; Inorganic Chemistry; Molecular; Optical and Plasma Physics; Physical Chemistry; Solid State Physics
• ISSN: 0022-4766; 1573-8779
• DOI: 10.1007/s10947-010-0002-6

Using the density functional theory method at the B3LYP/6-31G( d,p ) theory level, the formation of hydrogen bonded complexes of L -cysteine with selenious and selenic acids is studied. In both cases, complexes formed through the carboxyl group of cysteine mostly arise, their enthalpy of formation being of -19kcal/mol to -21 kcal/mol and the free energy of -6kcal/mol to -9kcal/mol. The primary act of interaction in the system of hydroxyl-containing selenium compound — α-aminoacid, including the mutual orientation of reactant molecules and the formation of intermolecular hydrogen bonds is likely to a serve as prerequisite for the thiol group to be able to participate in the next stages (including deeper chemical transformations) of biologically significant reactions.