The mechanism of uptake of cobalt ions by Neurospora crassa.
Uptake of Co(2+) by 3-day-old mycelia of Neurospora crassa involves cell-surface binding as well as transport into the intracellular space. The surface binding is rapid and accounts for 30-40% of the total Co(2+) uptake. Transport of Co(2+) occurs at a rate of 40mug/h per 100mg dry wt. Surface binding and overall uptake show different temperature dependence. Metabolic inhibitors such as azide, dinitrophenol and fluoride depress transport of Co(2+). The overall uptake of Co(2+) exhibits a high K(m) value and hence the concentration mechanism is one of low ;affinity' for the metal. The uptake of Co(2+) varies linearly with pH in the range pH3 to pH6. Mg(2+) inhibits both surface binding and transport of Co(2+). It is suggested that the system that transports Mg(2+) is also involved in Co(2+) uptake by N. crassa.
D001386:Azides / Q000494:pharmacology; D001665:Binding Sites; D001693:Biological Transport, Active; D002462:Cell Membrane; D003035:Cobalt / Q000378:metabolism*; D004140:Dinitrophenols / Q000494:pharmacology; D005459:Fluorides / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D009491:Neurospora / Q000378:metabolism*; D013696:Temperature; D014461:Ultracentrifugation
D001386:Azides; D004140:Dinitrophenols; D003035:Cobalt; D008274:Magnesium; D005459:Fluorides