Immunochemical studies of human urinary trypsin inhibitor.
Antisera against purified urinary trypsin inhibitor (UTI-I, molecular weight 67,000) and UTI-III (molecular weight 23,000) were first produced in rabbits. Both anti-UTI-I and anti-UTI-III sera formed a single immunoprecipitin line with human plasma inter-alpha-trypsin inhibitor (I alpha TI), whereas two immunoprecipitin lines were formed with crude urine. It was speculated that both UTI-I and UTI-II might be present in normal human urine. In the present study, the inhibitory effects of anti-UTI sera on UTI activity were examined by three different assay methods. The results indicated that the inhibitory effect was almost immediate. Although the inhibitory effect of anti-UTI-III serum on UTI-III was almost of the same degree of completeness for the three assay methods. UTI-I was partially inhibited by the anti-UTI-I serum when residual trypsin activity was measured by the caseinolytic or fibrinolytic assay method. This discrepancy was considered to be due to the difference in conformational change between UTI-I and UTI-III by antigen-antibody reaction.
D000510:Alpha-Globulins / Q000276:immunology; D000939:Epitopes / Q000276:immunology; D006801:Humans; D005779:Immunodiffusion; D008970:Molecular Weight; D014361:Trypsin Inhibitors / Q000276:immunology / Q000652:urine*
D000510:Alpha-Globulins; D000939:Epitopes; D014361:Trypsin Inhibitors; C011877:inter-alpha-inhibitor