[Demonstration of 2 enzymes with beta-galactosidase activity in Rhizobium meliloti]

The beta-galactosidase (EC 3.2.1.23) activities of wild-type Rhizobium meliloti and its lactose slow-hydrolyzing mutant have been compared. The properties of the enzyme are very different in each strain. These differences allow us to prove that two enzymes with a beta-galactosidase activity can be found in the wild-type whereas only one enzyme remains in the mutant strain.