Effects of dextran sulfate on aprotinin activity.

Dextran sulfate has an action on aprotinin activity similar to that seen with heparin: preincubation of dextran sulfate with aprotinin enhanced the inhibitory effect of aprotinin on the esterolytic activity of trypsin, but did not change the effect on the proteolytic activity of trypsin or on the esterolytic and proteolytic activities of chymotrypsin. The enhancing effects of heparin and dextran sulfate were not due to increase in the active form of aprotinin which reacts with trypsin, but rather due to a change in the aprotinin molecule which would lead to an increase in aprotinin activity.