Enzymes of the Poly-beta-Hydroxybutyrate and Citric Acid Cycles of Rhizobium japonicum Bacteroids.
The activities of several enzymes of the citric acid and poly-beta-hydroxybutyrate cycles were measured in Rhizobium japonicum 3I1B-143 bacteroids which had been isolated from soybean nodules by sucrose gradient centrifugation. During the period of developing nitrogenase activity, the specific activity of fumarase, hydroxybutyrate dehydrogenase, beta-ketothiolase, and pyruvate dehydrogenase complex increased whereas acetoacetate-succinyl-CoA transferase and isocitrate dehydrogenase decreased. Malate dehydrogenase activity remained constant. The amount of available acetyl-CoA, based on pyruvate dehydrogenase activity, should be sufficient to support both metabolic cycles concurrently. The temporal relationship between nitrogenase activity and poly-beta-hydroxybutyrate accumulation has been reexamined.
Karr
D B
DB
Department of Biochemistry and Interdisciplinary Plant Biochemistry-Physiology Group, University of Missouri-Columbia, Columbia, Missouri 65211.
Waters
J K
JK
Suzuki
F
F
Emerich
D W
DW