Properties of a Na+/galactose(glucose) symport system in Vibrio parahaemolyticus

Rafiquel I. Sarker, Wakano Ogawa, Masaaki Tsuda, Shuji Tanaka, Tomofusa Tsuchiya

Research output: Contribution to journalArticle

Abstract

We have investigated galactose transport in a mutant strain of Vibrio parahaemolyticus that lacks a glucose-PTS (phosphoenolpyruvate:carbohydrate phosphotransferase system) and a trehalose-PTS. Cells of the V. parahaemolyticus actively transported D-galactose and Na+ greatly stimulated the transport. Maximum stimulation of D-galactose transport activity was observed at 10 mM NaCl, and Na+ could be replaced with Li+. Addition of galactose to the cell suspension under anaerobic conditions elicited Na+ uptake. Therefore, we conclude that this organism accomplishes galactose transport by a Na+/solute symport mechanism. Judging from inhibition results, D-galactose, D- glucose and to a lesser extent α-D-fucose are substrates of this transport system. The Na+/galactose symport system exhibited a high affinity for D-galactose (K(m): 40 μM) and showed a relatively lower affinity for D-glucose (K(m): 420 μM), but the maximum velocities for galactose and glucose transport were almost same (about 52 nmol/min per mg protein). The Na+/D-galactose symport system was induced by either D-galactose or α-D-fucose, and repressed by D-glucose.

Original languageEnglish (US)
Pages (from-to)149-156
Number of pages8
JournalBiochimica et Biophysica Acta - Biomembranes
Volume1279
Issue number2
DOIs
StatePublished - Mar 13 1996
Externally publishedYes

Keywords

  • Galactose
  • Glucose
  • Sodium
  • Symport
  • V. parahaemolyticus

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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