title: Purification of a trifunctional enzyme, catalysing three steps of the histidine pathway, from Neurospora crassa.
abstract: 1. A procedure is described for the purification of an enzyme from Neurospora crassa that has three catalytic functions. These are 1-N-(5'-phosphoribosyl)-ATP pyrophosphohydrolase, 1-N-(5'-phosphoribosyl)-AMP cyclohydrolase and histidinol dehydrogenase (l-histidinol-NAD oxidoreductase, EC 1.1.1.23), and are responsible for the catalysis of reactions 2, 3 and 10 in the histidine pathway. The ratio of these three catalytic activities remains approximately the same throughout the purification procedure. Evidence is presented that the purified preparations contain a single protein exhibiting association-dissociation equilibria.
mesh_terms: D000227:Adenine Nucleotides; D000429:Alcohol Oxidoreductases / Q000302:isolation & purification*; D000596:Amino Acids / Q000032:analysis; D000619:Aminohydrolases / Q000302:isolation & purification*; D002499:Centrifugation, Density Gradient; D002845:Chromatography; D002850:Chromatography, Gel; D004586:Electrophoresis; D006639:Histidine / Q000378:metabolism*; D008970:Molecular Weight; D009491:Neurospora / Q000201:enzymology*; D010428:Pentosephosphates; D010744:Phosphoric Monoester Hydrolases / Q000302:isolation & purification*
chemical_list: D000227:Adenine Nucleotides; D000596:Amino Acids; D010428:Pentosephosphates; D006639:Histidine; D000429:Alcohol Oxidoreductases; D010744:Phosphoric Monoester Hydrolases; D000619:Aminohydrolases