Fig. 3.
Purification on a Superose 12 column. Fractions no. 41 through 43 from the mono-Q column (see Fig 2) were combined, concentrated, and loaded onto a Superose 12 column. PTP activity of fractions from normal (•) and PV (○) samples represents the data obtained from 2 μL of each 0.5-mL fraction eluted from the column and assayed with 32P-labeled ENDYINASL as a substrate. The inset represents the calibration of the Superose 12 column with standard molecular weight markers (apoferritin, 443,000; b-amylase, 200,000; alcohol dehydrogenase, 150,000; and carbonic anhydrase, 29,000). The PTP activity peaked at fraction 27.25, which corresponded to 170 kD based on linear regression analyses. A representative figure from three experiments with similar results is shown. Each experiment was performed with blood samples from different normal volunteers and PV patients.