Literature has been published stating that the optimal pH for lactase activity is 4.8 with lactose. At this pH, what would be the closest value to the charge on the catalytically active amino acids? (Assume the pKa of the COOH group is 4.5)

Which statement explains why the bonds between non metals tend to be covalent? the bonds are found to be nondirectional they have large differences in electronegativity they have small differences in electronegativity they have ions that produce an electrostatic pull