beta-galactosidase and the lactose operon.
D000595:Amino Acid Sequence; D000906:Antibodies; D003460:Crystallization; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D005696:Galactosidases / Q000235:genetics*; D005816:Genetic Complementation Test; D007763:Lac Operon; D009154:Mutation; D014961:X-Ray Diffraction; D001616:beta-Galactosidase / Q000235:genetics*
D000906:Antibodies; D005696:Galactosidases; D001616:beta-Galactosidase