Flavin adenine dinucleotide disodium salt hydrate

Trifluoracetic acid (TFA) was purchased from Fluka, Germany; triethylammonium bicarbonate (TEAB) was purchased from Sigma, St. Louis, MO, USA; heptafluorobutyric acid (HFBA) was purchased from Acros, Geel, Belgium; formic acid from Merck, Germany; acetonitrile from Fisher Chemical, Leicestershire, UK. Trypsin modified sequencing grade was obtained from Promega, Madison, WI, USA; flavin adenine dinucleotide disodium salt hydrate (FAD) was purchased from Sigma, St. Louis, MO, USA. A custom polyclonal sheep antibody was raised against human recombinant renalase1 and purified by Pocard Ltd. (Moscow, Russia). A monoclonal anti-rabbit/sheep IgG antibody conjugated with horseradish peroxidase was from IMTEK (Moscow, Russia) (see also [14] ).

GO (4 mg/mL, water dispersion) was purchased from Graphenea (Spain). Analytical grade chemicals were used with no further purification. All solutions were prepared with ultra pure deionized water. Glucose oxidase (GOD type VII from Aspergillus niger, EC 1.1.3.4, 168 U/mg), catalase (CAT from bovine liver, EC 1.11.1.6, 2,000-5,000 U/mg), peroxidase from horseradish (HRP, EC 1.11.1.7, 250-330 U/mg), flavin adenine dinucleotide (FAD disodium salt hydrate), β-Dglucose and DDAB were purchased from Sigma-Aldrich (Italy). GOD, HRP, CAT and FAD solutions (100 µM) were prepared in 50 mM phosphate buffer pH 7.4 and stored at 4 °C. β-Dglucose solution (100 mM) was prepared in 50 mM phosphate buffer pH 7.4 and allowed to mutarotate at room temperature overnight before use. DDAB solution (20 mM) was prepared in chloroform and stored at 4 °C.