Isolation of copper-binding proteins from activated sludge culture

Six copper-binding microbial proteins were isolated from activated sludge c ultures grown on media containing copper at various concentrations. Molecul ar weights among isolated proteins were ranged from 1.3k to 174k dalton. Is olated proteins were compared for their copper binding capabilities. Protei ns isolated from cultures grown in the presence of copper in the growth med ia exhibited higher copper binding capabilities than those isolated from th e culture grown in the absence of copper. The highest metal uptake of 61.23 (mol copper/mol protein) was observed by a protein isolated from a culture grown with copper at a concentration of 0.25 mM. This isolated protein (CB P2) had a molecular weight of 24k dalton. Other protein exhibited copper bi nding capability of 4.8-32.5 (mol copper/mol protein).