A Rapid Isolation of Phosphoribosyladenosine Triphosphate Synthetase and Comparison to Native Enzyme

Phosphoribosyladenosine triphosphate (PR-ATP) synthetase, the first enzyme in the biosynthesis of histidine, prepared by previously published methods from Salmonella typhimurium is shown to be contaminated by histidase. Construction of a bacterial strain deleting histidase but producing high levels of PR-ATP synthetase is reported. A new rapid isolation procedure based on two unique solubility properties which obviate use of chromatography columns gave pure enzyme in high yield. Stability properties of the enzyme were studied and three sets of conditions under which the enzyme may be stored for months without loss of activity or histidine sensitivity were found. Immunological studies demonstrated an interesting difference between the PR-ATP synthetase in a crude bacterial extract and the purified enzyme.