title: Inhibition of Glutamine Synthetase from Pea by Tabtoxinine-beta-lactam.
abstract: Tabtoxinine-beta-lactam, a hydrolytic product of tabtoxin produced by Pseudomonas syringae pv. tabaci, apparently inactivates pea seed glutamine synthetase. Inhibition of the enzyme's initial velocity is linear over a range of 0.5 to 5 millimolar tabtoxinine-beta-lactam in the presence of 10 millimolar glutamate. A method for the purification of glutamine synthetase from dried peas is presented which gives a 30% yield with a 2,000-fold increase in specific activity. A method for obtaining highly purified tabtoxinine-beta-lactam and tabtoxin in good yields is also presented. The authenticity and purity of tabtoxinine-beta-lactam and tabtoxin were verified by chromatography, biological activity, and (1)H and (13)C nuclear magnetic resonance spectroscopy.
authors: Department of Plant Pathology, University of Wisconsin-Madison and United States Department of Agriculture, Agricultural Research Service.
authors: M D
authors: MD
authors: Thomas
authors: P J
authors: PJ
authors: Langston-Unkefer
authors: T F
authors: TF
authors: Uchytil
authors: R D
authors: RD
authors: Durbin