title: Electrocatalysis in proteins, nucleic acids and carbohydrates.
abstract: The ability of proteins to catalyze hydrogen evolution has been known for more than 80 years, but the poorly developed d.c. polarographic "pre-sodium wave" was of little analytical use. Recently, we have shown that by using constant current chronopotentiometric stripping analysis, proteins produce a well-developed peak H at hanging mercury drop and solid amalgam electrodes. Peak H sensitively reflects changes in protein structures due to protein denaturation, single amino acid exchange, etc. at the picomole level. Unmodified DNA and RNA do not yield such a peak, but they produce electrocatalytic voltammetric signals after modification with osmium tetroxide complexes with nitrogen ligands [Os(VIII)L], binding covalently to pyrimidine bases in nucleic acids. Recently, it has been shown that six-valent [Os(VI)L] complexes bind to 1,2-diols in polysaccharides and oligosaccharides, producing voltammetric responses similar to those of DNA-Os(VIII)L adducts. Electrocatalytic peaks produced by Os-modified nucleic acids, proteins (reaction with tryptophan residues) and carbohydrates are due to the catalytic hydrogen evolution, allowing determination of oligomers at the picomolar level.
authors.affiliation: Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i. Kralovopolska 135, 612 65 Brno, Czech Republic. palecek@ibp.cz
authors.forename: Emil
authors.initials: E
authors.lastname: Paleček
authors.forename: Martin
authors.initials: M
authors.lastname: Bartošík
authors.forename: Veronika
authors.initials: V
authors.lastname: Ostatná
authors.forename: Mojmír
authors.initials: M
authors.lastname: Trefulka
mesh_terms: D002241:Carbohydrates / Q000737:chemistry*; D002384:Catalysis; D004247:DNA / Q000737:chemistry; D055664:Electrochemical Techniques; D004566:Electrodes; D006859:Hydrogen / Q000737:chemistry; D009696:Nucleic Acids / Q000737:chemistry* / Q000378:metabolism; D009993:Osmium Tetroxide / Q000737:chemistry; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism
chemical_list: D002241:Carbohydrates; D009696:Nucleic Acids; D011506:Proteins; D006859:Hydrogen; D004247:DNA; D009993:Osmium Tetroxide