DNA sequences and recombinant DNA molecules comprising at least a portion coding for all or part of subunits A and/or B of cholera toxin are prepared by enzymatic digestion of DNA of V. cholerae strains, isolating specific fragments and inserting them in appropriate vectors and subunits A and/or B of...http://www.google.com/patents/US4666837?utm_source=gb-gplus-sharePatent US4666837 - DNA sequences, recombinant DNA molecules and processes for producing the A and B subunits of cholera toxin and preparations containing so-obtained subunit or subunits
