Chicken muscle adenylate kinase was overproduced in soluble form under the transcriptional control of the bacterial phage lambda P_RP_L promoters regulated by temperature sensitive repressors. SDS-PAGE analysis demon-strated that the enzyme was produced to the extent of as much as 38% of the total cellular protein. The soluble recombinant enzyme can be released from bacterial cells and enriched to purity of more than 85% by the Johnson's freeze/thaw method. Mouse anti-rabbit muscle adenylate kinase monoclonal antibody can strongly crossreact with the recombinant enzyme.