Characterization of Purified Urinary Trypsin Inhibitors

Human urine was passed through Celite 545 column, and the non adsorbed eluate was adsorbed to Bentnite, then eluted with 2 % pyridine. The eluate was precipitated with ammonia sulfate, and the precipitate was dissolved, then passed through DEAE-Sephadex A-50, trypsin-Sepharose and Sephadex G-200. There were three types of urinary trypsin inhibitors (UTI) of m.w. of 69,000, 45,000, and 25,000 respectively. No difference in inhibitory spectra was observed among these three UTI’s. Purified UTI inhibited trypsin, chymotrypsin, and kallikrein. The inhibition of chymotrypsin did not exceed 50even at the high concentration of UTI. UTI inhibited plasmin to a lesser extent but no inhibition of thrombin, Cls, Clr or urokinase was observed.UTI had 7% carbohydrate and no HIS, PRO, or TRP was found in aminoacid analysis. UTI was not identical to α1A but related to inter α- trypsin inhibitor immunologically. Some persons excreted both UTI and α1A in the urine although most people did only UTI. Since α1A is not found in the urine of most people, UTI may not be the same as inter α-trypsin inhibitor which is filtered into the urine.