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 Boulter, J. R. Articles by Gielow, W. O. Search for Related Content PubMed PubMed Citation Articles by Boulter, J. R. Articles by Gielow, W. O.

 Previous Article  |  Next Article 

J Bacteriol. 1973 February; 113(2): 687-696
Copyright © 1973 American Society for Microbiology. All Rights Reserved.

Properties of D-Arabinose Isomerase Purified from Two Strains of Escherichia coli

¹ Department of Biological Sciences, Section of Biochemistry and Molecular Biology, University of California, Santa Barbara, California 93106

ABSTRACT

D-Arabinose isomerase (EC 5.3.1.3) has been isolated from L-fucose-induced cultures of Escherichia coli K-12 and D-arabinose-induced cultures of E. coli B/r. Both enzymes were homogeneous in an ultracentrifuge and migrated as single bands upon disc electrophoresis in acrylamide gels. The s_20,w was 14.5 x 10^–13 sec for the E. coli K-12 enzyme and 14.3 x 10^–13 sec for the E. coli B/r enzyme. The molecular weight, determined by high-speed sedimentation equilibrium, was 3.55 ± 0.06 x 10⁵ for the E. coli K-12 enzyme and 3.42 ± 0.04 x 10⁵ for the enzyme isolated from E. coli B/r. Both enzyme preparations were active wth L-fucose or D-arabinose as substrates and showed no activity on any of the other aldopentoses or aldohexoses tested. With the E. coli K-12 enzyme, the K_m was 2.8 x 10^–1M for D-arabinose and 4.5 x 10^–2M for L-fucose; with the E. coli B/r enzyme, the K_m was 1.7 x 10^–1M for D-arabinose and 4.2 x 10^–2M for L-fucose. Both enzymes were inhibited by several of the polyalcohols tested, ribitol, L-arabitol, and dulcitol being the strongest. Both enzymes exhibited a broad plateau of optimal catalytic activity in the alkaline range. Both enzymes were stimulated by the presence of Mn²⁺ or Co²⁺ ions, but were strongly inhibited by the presence of Cd²⁺ ions. Both enzymes were precipitated by antisera prepared against either enzyme preparation. The amino acid composition for both proteins has been determined; a striking similarity has been detected. Both enzymes could be dissociated, by protonation at pH 2 or by dialysis against buffer containing 8 M urea, into subunits that were homogeneous in an ultracentrifuge and migrated as single bands on disc electrophoresis in acrylamide gels containing urea. The molecular weight of the subunit, determined by high-speed sedimentation equilibrium, was 9.09 ± 0.2 x 10⁴ for the enzyme from E. coli K-12 and 8.46 ± 0.1 x 10⁴ for the enzyme from E. coli B/r. On the basis of biophysical studies, both isomerases appear to be oligomeric proteins consisting of four identical subunits.

This article has been cited by other articles:

• Lee, D.-W., Jang, H.-J., Choe, E.-A., Kim, B.-C., Lee, S.-J., Kim, S.-B., Hong, Y.-H., Pyun, Y.-R. (2004). Characterization of a Thermostable L-Arabinose (D-Galactose) Isomerase from the Hyperthermophilic Eubacterium Thermotoga maritima. Appl. Environ. Microbiol. 70: 1397-1404 [Abstract] [Full Text]