the results indicated the presence of 4 beta-galactosidases : ( i ) a neutral beta-galactosidase ( lactase ) with optimum ph of 5.8 , ( ii ) an acid beta-galactosidase i with optimum ph of 3.4 , ( iii ) an acid beta-galactosidase ii with optimum ph of 4.6 , and ( iv ) a hetero beta-galactosidase with ph optimum of 7.6 .
C0083183
lactase
C0005220
beta-galactosidase