Surface plasmon resonance has been used for a biospecific interaction analysis between two macromolecules in real time. Determination of an antibody that is capable of specifically interacting with the native form of antigen is very useful for many biological and medical applications. Twenty monoclonal antibodies against the $alpha$ subunit of E. coli DNA polymerase III were screened for specifically recognizing the native form of protein using surface plasmon resonance. Only four monoclonal antibodies among them specifically recognized the native $alpha$ protein, although all of the antibodies were able to specifically interact with the denatured $alpha$ subunit. These antibodies failed to interfere with the interaction between the $ au$ and $alpha$ subunits that were required for dimerization of the two polymerases at the DNA replication fork. This real-time analysis using surface plasmon resonance provides an easy method to screen antibodies that are capable of binding to the native form of the antigen molecule and determine the biological interaction between the two molecules.