intracistronic alpha complementation involving escherichia coli beta-galactosidase occurs between the cyanogen bromide peptide cb2 , derived from residues 3-92 of beta-galactosidase ( langley , k.e. , fowler , a.v. , and zabin , i . ( 1975 ) , j. biol . chem . 250 , 2587 ) , and the defective beta-galactosidase from the z-deletion mutant strain m15 .
C0005220
beta-galactosidase
C0016955
galactosidase