Evidence for two transporters of sulfur and selenium oxyanions in Clostridium pasteurianum

Abstract

Kinetic uptake studies of the inorganic anions [Formula: see text], [Formula: see text], and [Formula: see text] into Clostridium pasteurianum showed that these dianions transport systems obeyed Michaelis–Menten kinetics. Analysis of Km and Ki values for these dianions suggest there were two ports of entry for these oxyanions into the cell, with [Formula: see text] and [Formula: see text] having a common porter and [Formula: see text] having a separate transporter. The practical importance of these experiments is related to the environment where some sediments contaminated with inorganic selenium compounds are in the concentration range which approximates the Km values for [Formula: see text](50 μM)/[Formula: see text](65 μM) in C. pasteurianum.