Protein and carbohydrate moieties of a preparation of β-lactamase II

1. A crystalline preparation of β-lactamase II has been separated into two moieties by gel filtration on a column of Sephadex G-100. 2. The first moiety consisted mainly of carbohydrate and showed virtually no β-lactamase activity. 3. The second moiety was a protein of molecular weight 22500, which was enzymically active. 4. The protein moiety, like the original protein–carbohydrate complex, required Zn²⁺ for β-lactamase activity. It did not differ significantly from the complex in its behaviour to a number of cephalosporin substrates, but was less stable to heat than the complex. 5. About 30% of the total β-lactamase activity was lost when the protein–carbohydrate complex was separated into the two moieties. This activity was regained when the protein and carbohydrate moieties were mixed, but the mixture did not show the heat stability of the original complex.