Figure 4.

Phosphatase activity in S10 fractions of HeLa cells mock-infected or infected with 20 pfu of HSV-1(F), R3616, or R8300 per cell. The procedures were carried out as described. (A) Fraction of residual radioactivity in eIF-2α-³²P after reaction with variable amounts of S10 fractions from mock-infected or infected cells. (B) Effect of inhibitor 2 on the rate of dephosphorylation of eIF-2α-³²P by the phosphatase activity in the S10 fractions. The results are expressed as the relative rate of activity seen in duplicate samples containing no added inhibitor 2. (C) [³²P]phosphorylase phosphatase activity. The procedure was the same as in A except that the dephosphorylation of [³²P]phosphorylase by the S10 fractions was assayed. The results are an average of two determinations and are expressed as the percentage of [³²P]phosphorylase remaining, when compared with zero time samples. (D) Effect of inhibitor 2 on the relative rate of [³²P]phosphorylase phosphatase activity. The assay was done as described in B.