title: Complete purification and general characterization of FAD synthetase from rat liver.
abstract: Flavin adenine dinucleotide synthetase (ATP:FMN adenylyltransferase, EC 2.7.7.2) was purified about 10,000-fold from the high-speed supernatant of rat liver by a sequence of ammonium sulfate fractionation and column chromatographies on DEAE-Sephadex (A-50), chromatofocusing, FMN-agarose affinity, and Sephadex G-200. The specific activity of the purified enzyme was 133 units (nanomoles of FAD formed per min at 37 degrees C)/mg of protein. This preparation was free from contaminating FAD pyrophosphatase. The apparent molecular weight was estimated to be 97,000 by gel filtration on Sephadex G-200. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed an apparent subunit molecular weight of 53,000. Hence, the enzyme is a dimer of approximately 100,000. The enzyme was found most active at pH 7.1, requires Mg2+, and is essentially irreversible in the direction of FAD formation. Kinetic analysis gave Km values of 9.6 microM for FMN and 53 microM for ATP.
mesh_terms: D000818:Animals; D002413:Cations, Divalent; D002845:Chromatography; D004355:Drug Stability; D004591:Electrophoresis, Polyacrylamide Gel; D005182:Flavin-Adenine Dinucleotide / Q000096:biosynthesis; D005590:Fractional Precipitation; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008099:Liver / Q000201:enzymology*; D046911:Macromolecular Substances; D008274:Magnesium / Q000494:pharmacology; D008970:Molecular Weight; D009713:Nucleotidyltransferases / Q000302:isolation & purification* / Q000378:metabolism; D051381:Rats
chemical_list: D002413:Cations, Divalent; D046911:Macromolecular Substances; D005182:Flavin-Adenine Dinucleotide; D009713:Nucleotidyltransferases; C020143:FMN adenylyltransferase; D008274:Magnesium