Characterization of 1-phosphofructokinase from halophilic archaebacterium Haloarcula vallismortis

1-Phosphofructokinase (EC 2.7.1.56) (1PFK) was purified and characterized for the first time from an archaebacterial halophile Haloarcula vallismortis. The purification procedure involving (NH4)2SO4 fractionation, (NH4)2SO4-mediated chromatography on Sepharose 4B, CM-cellulose chromatography, hydrophobic chromatography on phenyl Sepharose and adsorption chromatography on hydroxylapatite yielded a preparation with a specific activity of 128 and 100-fold purification. From gel filtration and sucrose density gradient ultracentrifugation, the apparent molecular mass of halobacterial 1PFK was found as 76 +/- 5 kDa. The halobacterial 1PFK appears to be monomeric and the possibility of an unstable phosphoenzyme intermediate during its catalysis could not be ruled out. As in the case of many halobacterial enzymes, the 1PFK was found to be halophilic and thermostable. Other catalytic features of halobacterial 1PFK were similar to its counterparts from eubacterial sources.