when the uptake of 0.1 mm labeled sulfate was determined in the presence of 5 mm of various anions in the incubation medium , cis inhibitions were observed when sulfate was driven by a proton gradient ( out greater than in ) , a sodium gradient ( out greater than in ) , or a p-aminohippurate gradient ( in greater than out ) .
C0003075
anions
C0038720
sulfate