Psoriatic scale extracts were fractioned by using polyacrylamide gel isoelectric focusing (PAGIF) and preparative electrofocusing in granulated gel (PEGG). The largest protein fraction was found with Ip at pH 4.8--5.0, and the main protein bands within pH values 4.0--7.5. PEGG separated three main fractions with plasminogen activator or trypsin-like esterase activity with isoelectric points at pH 6.5--6.6, 5.4--6.2 and 4.9. The enzyme with Ip at pH 6.5--6.6 hydrolyzed trypsin substrates but lacked plasminogen activator capacity. The enzyme with Ip at pH 5.4--6.2 showed both activities but the third enzyme with plasminogen activator capacity with Ip at pH 4.9 was without detectable esterolytic activity towards substituted basic amino acid esters. The third enzyme was prominent in KCl-extract and the second in KSCN-extract. The first was equal in both extracts. The enzyme with Ip at pH 4.9 is possibly of bacterial origin while the plasminogen activator with Ip at pH 5.4--6.2 extracted in KSCN probably represents tissue activator of psoriatic scales.