Incorporation of 35S-Methionine or 35S-Cystine into Polypeptide Protease Inhibitor in the Rabbit Skin with Healing Inflammation (Preliminary Report)

The specific inhibitor of SH-dependent skin protease responsible for the development of Arthus-type inflammation was isolated from the skin site and highly purified by chromatography. The gradual cessation of the inflammatory process was associated with a local increase of the inhibitor. The inhibitor (polypeptide) behaved as a homogeneous substance in electrophoresis and ultra-centrifugation. The constituent amino-acids of the polypeptide were as follows: Cys, Met, Asp, Thr, Ser, Glu, Pro, Ala, Gly, Val, Len, Ileu, Phe, Lys, His, Arg and HO-pro. The labeled amino-acids (35S-methionine or 35S-cystine) given intravenously were incorporated into the inhibitor; approximately 87 per cent of radioactivity in the hydrolysed inhibitor was found in methionine and approximately 13 per cent in cystine. The observations suggested possible synthesis of this inhibitor in the inflamed skin site.