The effect of salt on the Michaelis Menten constant of the HIV-1 protease correlates with the Hofmeister series.

The effect of different types of salt on the proteolytic activity of HIV-1 protease was studied. At a similar ionic strength, the enzyme activity changed according to the salting out effect of the ions used (Hofmeister series). Kinetic studies showed that a stronger salting out effect of the ions rather than the higher ionic strength per se increased the affinity to the substrate (Km) but in general did not alter the Kcat value.