This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Tabita, F R Articles by McFadden, B A Search for Related Content PubMed PubMed Citation Articles by Tabita, F R Articles by McFadden, B A

 Previous Article  |  Next Article 

J Bacteriol. 1976 June; 126(3): 1271-1277

Molecular and catalytic properties of ribulose 1,5-bisphosphate carboxylase from the photosynthetic extreme halophile Ectothiorhodospira halophila.

ABSTRACT

D-Ribulose 1,5-bisphosphate (RuBP) carboxylase has been purified from the photosynthetic extreme halophile Ectothiorhodospira halophila. Despite a growth requirement for almost saturating sodium chloride in the medium, both crude and homogeneous preparations of RuBP carboxylase obtained from this organism were inhibited by salts. Sedimentation equilibrium analyses showed the enzyme to be large (molecular weight: 601,000). The protein was composed of two types of polypeptide chains of 56,000 and of 18,000 daltons. The small subunit appeared to be considerably larger than the small subunit obtained from the RuBP carboxylase isolated from Chromatium, an organism related to E. halophila. Amino acid analyses of hydrolysates of both E. halophilia and Chromatium RuBP carboxylases were very similar. Initial velocity experiments showed that the E. halophila RuBP carboxylase had a Km for ribulose diphosphate of 0.07 mM and a Km for HCO3- of 10 mM. Moreover, 6-phospho-D-gluconate was found to markedly inhibit the E. halophila carboxylase; a Ki for phosphogluconate of 0.14 mM was determined.

This article has been cited by other articles:

• Hoeft, S. E., Blum, J. S., Stolz, J. F., Tabita, F. R., Witte, B., King, G. M., Santini, J. M., Oremland, R. S. (2007). Alkalilimnicola ehrlichii sp. nov., a novel, arsenite-oxidizing haloalkaliphilic gammaproteobacterium capable of chemoautotrophic or heterotrophic growth with nitrate or oxygen as the electron acceptor. Int. J. Syst. Evol. Microbiol. 57: 504-512 [Abstract] [Full Text]