title: Fructose-1,6-bisphosphatase from Synechococcus leopoliensis. Substrate-dependent dimer-tetramer interconversion.
abstract: Extracts of Synechococcus leopoliensis (Anacystis nidulans) contain two forms of D-fructose-1,6-bisphosphatase (EC 3.1.3.11) previously designated as forms A and B [Gerbling, K.-P., Steup, M., and Latzko, E. (1984) Arch. Microbiol. 137, 109-114]. Form B, which probably represents the major part of the total extractable fructose-1,6-bisphosphatase activity, has been purified to apparent homogeneity. Gel filtration, non-denaturing polyacrylamide gel electrophoresis, and cross-linking with bis(sulfosuccinimidyl)suberate revealed that the fructose-1,6-bisphosphatase B exists in either a dimeric or in a tetrameric subform, depending upon the absence or presence of fructose-1,6-bisphosphate and Mg2+. The dimer--tetramer interconversion was readily reversible. The results provide evidence for a two-step activation of fructose-1,6-bisphosphatase B involving the reduction of the dimeric subform and the subsequent substrate-dependent conversion of the reduced dimer to a reduced tetramer, which is the only catalytically active state. In contrast to form B, no substrate-dependent interconversion was detected with form A from S. leopoliensis.
authors.forename: K P
authors.initials: KP
authors.lastname: Gerbling
authors.forename: M
authors.initials: M
authors.lastname: Steup
authors.forename: E
authors.initials: E
authors.lastname: Latzko
mesh_terms: D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D000458:Cyanobacteria / Q000201:enzymology*; D004591:Electrophoresis, Polyacrylamide Gel; D006597:Fructose-Bisphosphatase / Q000302:isolation & purification / Q000378:metabolism*; D046911:Macromolecular Substances; D010084:Oxidation-Reduction; D011489:Protein Denaturation
chemical_list: D046911:Macromolecular Substances; D006597:Fructose-Bisphosphatase