Direct clean-up and analysis of ribonucleosides in physiological fluids

We describe the group-selective separation and quantification of unmodified, modified and hypermodified ribonucleosides in physiological fluids (urine, serum) by on-line multidimensional high-performance affinity chromatography (HPAC)-reversed-phase liquid chromatography (RPLC). The excretion levels and patterns of ribonucleosides such as N1-methyladenosine, N1-methylinosine, N2-methylguanosine, N2-dimethylguanosine, N6-carbamoylthreonyladenosine and 2-pyridone-5-carboxamido-N-ribofuranoside were determined in urines from a control group and from patients with different diseases. The HPAC-RPLC method applied represents a powerful tool, e.g. as a non-invasive screening test, a method to investigate disorders in ribonucleoside and/or RNA metabolism, a method for drug monitoring during nucleoside chemotherapy, and a method to study renal ribonucleoside reutilization.     

Investigations of mitochondrial adenine nucleotide translocation by means of nucleotide analogs.

ATP and ADP are transferred across the inner mitochondrial membrane by means of a carrier (translocator), an inner membrane integral lipoprotein. Translocation of the adenine nucleotides occurs in two steps: specific binding and transport. By using substrate analogs with modified adenine, phosphate, or ribose moieties it is possible to check which structural properties of the substrate are essential for binding and transport.     

Molar extinction coefficients of some carbohydrates in aqueous solutions

Molar extinction coefficients of some carbohydrates viz. l-arabinose (C₅H₁₀O₅), d-glucose (C₆H₁₂O₆), d-mannose (C₆H₁₂O₆), d-galactose (C₆H₁₂O₆), d(-) fructose (C₆H₁₂O₆) and maltose (C₁₂H₂₄O₁₂) in aqueous solutions have been determined at 81, 356, 511, 662, 1173 and 1332 keV by gamma ray transmission method in a narrow beam good geometry set-up. These coefficients have been found to depend upon the photon energy following a 4-parameter polynomial. These extinction coefficients for different sugars having the same molecular formula have same values varying within experimental uncertainty. Within concentration ranges studied, Beer-Lambert law is obeyed very well.     

Zur Frage der klinisch-biochemischen Analyse modifizierter Ribonucleoside in Harn und Serum

Ohne Zusammenfassung

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On the problem of the clinical-biochemical analysis of modified ribonucleosides in urine and serum

     

N,N-Dimethyl-2-Mercaptoethylammoniumchlorid als Thiolkomponente der OPA-Methode in der Analytik von Milchprodukten

Ohne Zusammenfassung

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N,N-Dimethyl-2-mercaptoethylammonium chloride used as thiol component in the OPA-method for the analysis of milk products