Clinical situations with release of
proteinases from blood cells or tissues into the circulation may result in a marked decrease of blood
proteinase inhibitor content which in turn may result in a
capillary leak syndrome,
shock and even in exitus letalis. Replenishment of blood
proteinase inhibitors is of benefit in such situations. In this study the inhibitory potential of fresh plasma, fresh frozen plasma and the liquid
plasma protein preparation Biseko has been tested with the following
enzymes: human
leukocyte elastase, human
plasmin, human
matrix metalloproteinase-9, bovine
trypsin, bovine
chymotrypsin and rat liver lysosomal
cathepsins. The concentration of the
blood protein preparations resulting in 50% inhibition of constant amounts of each of the
enzymes has been determined by plotting residual activity vs. log of concentration of
blood protein preparation in
enzyme assays. From these IC50 values inactivation ratios for 1 mg and 1 ml of the
blood protein preparations was calculated. These inactivation ratios show an equal suitability of fresh plasma, fresh frozen plasma or full
plasma proteins for replenishment of plasma
proteinase inhibitory potential in vitro. As additional finding, commercial preparations of
human serum albumin exert a surprisingly high inhibitory potential to lysosomal
cathepsins.