Trypsin-inhibitory activities of acid-stable fragments of the inter-alpha-trypsin inhibitor in inflammatory and uraemic conditions.

The concentration in serum of the acid-stable Mr 30.000 fragment of the Inter-alpha-Trypsin Inhibitor (SPI), and the acid-stable Mr 14.000 fragment of the inhibitor prepared by trypsin by digestion of the acid-precipitated serum proteins (API) was determined. A considerable increase in concentration of SPI and a decrease in concentration of API were observed in inflammatory conditions. In uraemic conditions the concentration of SPI was increased while that of API was unchanged.