A convenient and efficient procedure for the purification of cytidine deaminase (EC 3.5.4.5) from Escherichia coli is reported. The key step involves adsorption of the enzyme from a crude ammonium sulfate fraction onto a cytidine-containing affinity resin, followed by elution with 0.5 M borate buffer. Subsequent chromatography on DEAE-Sepharose results in an overall 1690-fold purification, yiel...

The first attempt to demonstrate cystathionine synthetase from animal tissues was reported by Binkley (1). This author reported the preparation from rat liver of an extract that catalyzed the synthesis of cystathionine from serine and homocysteine. A second preparation containing cystathionase was utilized for assaying the activity of the synthesis enzyme. Numerous difficulties prevented this a...

Prephenate dehydrogenase of Pseudomonas aeruginosa is unstable in crude extracts or following its partial purification by gel-filtration. However, when ion-exchange chromatography (DEAE-cellulose) is the initial purification step, a stable enzyme preparation is recovered. The enzyme, having a molecular weight of approximately 150,000, has a K, for prephenate of 0.05 mM, and is inhibited competi...

Tryptophanyl-tRNA synthetase has been purified from a lymphocyte-rich fraction of blood cells of patients with chronic lymphocytic leukemia. Normal lymphocytes, other blood cells, and skin also contain the enzyme. After a 240-fold purification by column chromatography, a further purification was obtained by isoelectric focusing, which revealed an isoelectric point of 5.2 to 5.3. The enzyme is s...

Abyssomicin C and its atropisomer are potent inhibitors of bacterial folate metabolism. They possess complex polycyclic structures, their biosynthesis has been shown to involve several unusual enzymatic transformations. Using a combination synthesis in vitro assays we reveal that AbyV, cytochrome P450 enzyme from the aby gene cluster, catalyses key late-stage epoxidation required for installati...