'Molten-globule' state accumulates in carbonic anhydrase folding.

Kinetics of folding and unfolding of bovine carbonic anhydrase B were monitored by circular dichroism, viscometry and esterase activity. It was shown that kinetic intermediate states accumulating in folding process reveal a native-like compactness and secondary structure but have a symmetrized average environment of aromatic side groups and no esterase activity. These properties allow one to consider these intermediate states as the 'molten-globule' state of a protein molecule previously described by us for several equilibrium forms of bovine and human alpha-lactalbumins and bovine carbonic anhydrase B.