A study of proteases and protease-inhibitor complexes in biological fluids

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摘要：

We have (a) screened a variety of cell lines and body fluids for and (b) studied the activity of bound to after exposing the complexes to partial degradation and/or denaturing procedures to unmask proteolytic activity. The respective results show (a) that the in urine and cell culture media are generally of lower molecular weight than those in plasma; and (b) that bound to recover the ability to attack macromolecular substrates after exposure to while retaining the electrophoretic mobility of the complex. This indicates that the and inhibitor are probably linked by covalent bonds. In contrast, other complexes formed between and inhibitors of lower molecular weight (such as or Kunitz inhibitors) are fully dissociated by (). The experiments described were based on a new procedure for detecting proteolytic enzyme activity in -gels. The method relies on solutions of nonionic detergents for extracting , after which the electrophoretic gel is applied to an indicator gel consisting of a fibrin- agar mixture. The method is sensitive, permitting the detection of in less than 1 mul of fresh plasma, and it is effective for resolving small differences in molecular weight. The procedure can be quantitated and, with minor modifications appropriate to each particular system, it has been applied to a broad spectrum of serine enzymes and proenzymes, including some that function in the pathways of , and kinin-generation. Other potential applications appear likely.

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Animals Humans Cell Line Plasminogen Activators alpha-Macroglobulins Agar Culture Media Protease Inhibitors Electrophoresis, Polyacrylamide Gel Methods