It is well established that many intracellular enzymes are oligomeric with dimers and tetramers being the most common of the possible subunit structures (1 ,2 ). Evaluation of the functional significance of the quaternary structure is an important part of the fundamental studies on the catalytic properties of an enzyme that are necessary to obtain a complete understanding of enzyme structure, function, mechanism, and applications (3 –5 ). For some enzymes the correlation between allosteric properties, subunit interactions, and enzyme activity is generally well understood. However, in many other enzymes, considerably less is known about the occurrence of subunit interactions or the significance of the oligomeric structure (6 –9 ).
