Gollop, R., Department of Biology, Ben-Gurion University of the Negev, PO Box 653, Beer Sheva, 84105, Israel
Santhaguru, K., Department of Biology, Ben-Gurion University of the Negev, PO Box 653, Beer Sheva, 84105, Israel
Avissar, Y.J., Department of Biology, Ben-Gurion University of the Negev, PO Box 653, Beer Sheva, 84105, Israel
Santhaguru, K., Department of Biology, Ben-Gurion University of the Negev, PO Box 653, Beer Sheva, 84105, Israel
Avissar, Y.J., Department of Biology, Ben-Gurion University of the Negev, PO Box 653, Beer Sheva, 84105, Israel
Control of the initial steps in heme biosynthesis in free-living Rhizobium sp. by culture conditions
Cell-free extracts obtained from free-living Rhizobium sp. in early stationary phase had three times as much 5-aminolevulinate synthase activity as did similar extracts from log phase cells. The level of 5-aminolevulinate dehydratase was also elevated at this point. The presence of 0.1 m M hemin in the culture medium prevented the transitory increase in enzyme activities during this early stationary phase. The effect of hemin was counteracted by 1 mg bovine serum albumin per milliliter medium. This control of the development of 5-aminolevulinate synthase and 5-aminolevulinate dehydratase activities by free hemin suggests a mechanism by which heme and globin formation might be coordinated for the synthesis of leghemoglobin in legume root nodules. © 1984 Springer-Verlag.
