Immunochemical Studies of Human Urinary Trypsin Inhibitor

Abstract

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 intera- trypsin inhibitor (IaTI), whereas two immunoprecipitin lines were formed with crude urine. It was speculated that both UTI-I and UTI-III 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.

Low Molecular Weight Trypsin-Plasmin Inhibitors Isolated from Papain Treated Urinary Trypsin Inhibitor

“…In normal human urine, the authors have shown that the main molecular form of UTI is UTI6, (8, 9, L2). Recently, similar acidstable inhibitors with the same antigenicity to UTIs have been found in human amniotic fluid ascites, and tumor fluids (23), as well as in plasma (24). Furthermore, the UTIs showed inhibitory effects not only for trypsh, chymotrypsin and plasmin, but also for human acrosomal protease acrosin (L4, 15).…”

Urinary Trypsin Inhibitor and Urokinase Activities in Renal Diseases

“…Thus, if renal function is decreased, a decrease of UK production and subsequently a decrease of its excretion in the urine, may be possible. On the other hand, the antigenicity of UTI is the same as that of plasma inter-a-trypsin inhibitor [2][3][4][5][6][7], and we have furthermore recently proved that anti-UTI antibody reacts to purified UTI and also human plasma prote in (euglobulin fraction) [12]. Based on these findings and the fact that relatively high lev els of UTI are present even in the urine of normal persons in contrast to weak activity of acid-stable protease inhibitors in the plasma (less than 3% of the total antitrypsin activity remaining after plasma is treated with acid) [13], UTI is considered to repre sent a product from a precursor protein (most probably from plasma inter-«-trypsin inhibitor) in the plasma and will tend to be readily excreted once produced.…”

Purification and Some Properties of a Low Molecular Weight Trypsin Inhibitor from Acute Pancreatitis Urine

“…They found that these UTIs had a molecular weight of from about 10,000 to 70,000 dal tons and the same antigenicity with serum IaTI [24][25][26][27], However, there was no report so far on a low molecular weight trypsin inhibitor from human urine.…”