THE KINETIC-STUDIES ON THE INTRAMOLECULAR SH, S-S EXCHANGE-REACTION OF BOVINE MERCAPTALBUMIN

Bovine mercaptalbumin (BMA) has 17 disulfide bonds and one SH group at Cys-34 which catalyzes the intramolecular SH, S-S exchange reaction (N-A isomerization, molecular aging) in the alkaline region at low ionic strength, resulting in the formation of the aged form (A-form). The aging reaction was completely reversible and strongly affected by environmental factors, such as pH, temperature, ionic strength, Ca2+, nonbranched short-chain fatty acids, etc. Disulfide configuration (or pairing of disulfide bonds) was affected by the environmental factors. Obtained results might support the concept of Klotz (1966) that protein conformation (or three-dimensional structure) is dependent upon (i) the primary structure and (ii) constituents of the solvent.